ISO/TS 18234-2:2006
(Main)Traffic and Travel Information (TTI) — TTI via Transport Protocol Expert Group (TPEG) data-streams — Part 2: Syntax, Semantics and Framing Structure (SSF)
Traffic and Travel Information (TTI) — TTI via Transport Protocol Expert Group (TPEG) data-streams — Part 2: Syntax, Semantics and Framing Structure (SSF)
ISO TS 18234-2:2006 establishes the method of referencing used within a TPEG data stream to allow a service provider to signal availability of the same service on another bearer channel or similar service data from another service. TPEG is a byte-oriented stream format, which may be carried on almost any digital bearer with an appropriate adaptation layer. TPEG messages are delivered from service providers to end-users, and are used to transfer application data from the database of a service provider to a user's equipment. The protocol is structured in a layered manner and employs a general purpose framing system which is adaptable and extensible, and which carries frames of variable length. This has been designed with the capability of explicit frame length identification at nearly all levels, giving greater flexibility and integrity, and permitting the modification of the protocol and the addition of new features without disturbing the operation of earlier client decoder models.
Informations sur le trafic et le tourisme (TTI) — Messages TTI via les flux de données du groupe d'experts du protocole de transport (TPEG) — Partie 2: Structure de syntaxe, de sémantique et de cadrage (SSF)
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Standards Content (Sample)
TECHNICAL ISO/TS
SPECIFICATION 18234-2
First edition
2006-06-01
Traffic and Travel Information (TTI) — TTI
via Transport Protocol Expert Group
(TPEG) data-streams —
Part 2:
Syntax, Semantics and Framing Structure
(SSF)
Informations sur le trafic et le tourisme (TTI) — Messages TTI via les
flux de données du groupe d'experts du protocole de transport
(TPEG) —
Partie 2: Structure de syntaxe, de sémantique et de cadrage (SSF)
Reference number
ISO/TS 18234-2:2006(E)
©
ISO 2006
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ISO/TS 18234-2:2006(E)
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ISO/TS 18234-2:2006(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Symbols and abbreviations . 2
4 Design principles. 3
4.1 TPEG transmission. 4
4.2 TPEG layer model . 5
5 Conventions and symbols . 7
5.1 Conventions . 7
5.2 Symbols . 7
6 Representation of syntax. 8
6.1 General. 8
6.2 Data type notation. 8
6.3 Application independent elements . 9
6.4 Application dependent elements . 13
6.5 Application design principles. 14
7 TPEG description. 15
7.1 Hierarchy (frame structure) . 15
7.2 Transport level . 18
7.3 Service level . 19
7.4 Service component multiplex level. 21
7.5 Service component level. 21
Annex A (normative) Character tables. 22
Annex B (normative) Method for coding quantities of objects . 23
Annex C (normative) CRC calculation . 25
Annex D (normative) Time calculation. 27
Annex E (informative) A description of the TPEG byte-stream using C-type notation. 30
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ISO/TS 18234-2:2006(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
In other circumstances, particularly when there is an urgent market requirement for such documents, a
technical committee may decide to publish other types of normative document:
— an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical experts in
an ISO working group and is accepted for publication if it is approved by more than 50 % of the members
of the parent committee casting a vote;
— an ISO Technical Specification (ISO/TS) represents an agreement between the members of a technical
committee and is accepted for publication if it is approved by 2/3 of the members of the committee casting
a vote.
An ISO/PAS or ISO/TS is reviewed after three years in order to decide whether it will be confirmed for a
further three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or ISO/TS is
confirmed, it is reviewed again after a further three years, at which time it must either be transformed into an
International Standard or be withdrawn.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO/TS 18234-2 was prepared by Technical Committee ISO/TC 204, Intelligent transport systems.
ISO/TS 18234 consists of the following parts, under the general title Traffic and Travel Information (TTI) — TTI
via Transport Protocol Expert Group (TPEG) data-streams:
⎯ Part 1: Introduction, numbering and versions
⎯ Part 2: Syntax, Semantics and Framing Structure (SSF)
⎯ Part 3: Service and Network Information (SNI) application
⎯ Part 4: Road Traffic Message (RTM) application
⎯ Part 5: Public Transport Information (PTI) application
⎯ Part 6: Location referencing applications
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ISO/TS 18234-2:2006(E)
Introduction
TPEG technology uses a byte-oriented stream format, which may be carried on almost any digital bearer with
an appropriate adaptation layer. TPEG messages are delivered from service providers to end-users, and are
used to transfer application data from the database of a service provider to a user’s equipment.
This document describes the Service and Network Information Application, which provides a means of
informing end-users about all possible services and their content which are considered relevant by a service
provider to either provide continuity of his services or inform the end-user about other related services. As
stated in the design criteria, TPEG is a bearer independent system. Therefore some rules are established for
the relation of information contents of the same service on different bearers. Also the mechanisms for
following a certain service on one single bearer have to be defined. For the receiver it is essential to find an
adjacent or similar service if it leaves the current reception area. Nonetheless, basic information describing the
service itself is necessary. For the ease of the user, e.g. the service name, the service provider name, the
operating time and many other hints are delivered by the TPEG-SNI application.
Also, general models for the hand-over and the referencing of services are developed and shown in detail. It is
important to note that this Part 2 of CEN ISO/TS 18234 (TPEG-SSF) is closely related to Part 3 (TPEG-SNI)
and so they must be used together, being dependent upon each other.
The Broadcast Management Committee of the European Broadcast Union (EBU) established the B/TPEG
project group in autumn 1997 with the mandate to develop, as soon as possible, a new protocol for
broadcasting traffic and travel-related information in the multimedia environment. The TPEG technology, its
applications and service features are designed to enable travel-related messages to be coded, decoded,
filtered and understood by humans (visually and/or audibly in the user’s language) and by agent systems.
One year later in December 1998, the B/TPEG group produced its first public specifications. Two documents
were released. Part 2 (TPEG-SSF, CEN ISO/TS 18234-2, this document) described the Syntax, Semantics
and Framing structure, which will be used for all TPEG applications. Part 4 (TPEG-RTM, CEN
ISO/TS 18234-4) described the first application, for Road Traffic Messages.
CEN/TC 278/WG 4, in conjunction with ISO/TC 204/WG 10, established a project group comprising the
members of B/TPEG and they have continued the work concurrently since March 1999. Since then two further
parts have been developed to make the initial complete set of four parts, enabling the implementation of a
consistent service. Part 3 (TPEG-SNI, CEN ISO/TS 18234-3) describes the Service and Network Information
Application, which is likely to be used by all service implementations to ensure appropriate referencing from
one service source to another. Part 1 (TPEG-INV, CEN ISO/TS 18234-1) completes the work, by describing
the other parts and their relationships; it also contains the application IDs used within the other parts.
In April 2000, the B/TPEG group released revised Parts 1 to 4, all four parts having been reviewed and
updated in the light of initial implementation results. Thus a consistent suite of specifications, ready for wide
scale implementation, was submitted to the CEN/ISO commenting process.
In November 2001, after extensive response to the comments received and from many internally suggested
improvements, all four parts were completed for the next stage: the Parallel Formal Vote in CEN and ISO. But
a major step forward has been to develop the so-called TPEG-Loc location referencing method, which
enables both map-based TPEG-decoders and non map-based ones to deliver either map-based location
referencing or human readable information. Part 6 (TPEG-Loc, CEN ISO/TS 18234-6) is now a separate
specification and is used in association with the other parts of CEN ISO/TS 18234 to provide comprehensive
location referencing. Additionally Part 5, the Public Transport Information Application (TPEG-PTI, CEN
ISO/TS 18234-5), has been developed and been through the commenting process.
This Technical Specification, CEN ISO/TS 18234-2, provides a full specification to the primitives used, framing,
time calculation, numbers and to specific rules such as CRC calculation.
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ISO/TS 18234-2:2006(E)
During the development of the TPEG technology a number of versions have been documented and various
trials implemented using various versions of the specifications. At the time of the publication of this Technical
Specification, all parts are fully inter-workable and no specific dependencies exist. This Technical
Specification has the technical version number TPEG-SSF_3.0/002.
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TECHNICAL SPECIFICATION ISO/TS 18234-2:2006(E)
Traffic and Travel Information (TTI) — TTI via Transport
Protocol Expert Group (TPEG) data-streams —
Part 2:
Syntax, Semantics and Framing Structure (SSF)
1 Scope
This Technical Specification establishes the method of referencing used within a TPEG data-stream to allow a
service provider to signal availability of the same service on another bearer channel or similar service data
from another service.
TPEG is a byte-oriented stream format, which may be carried on almost any digital bearer with an appropriate
adaptation layer. TPEG messages are delivered from service providers to end-users, and are used to transfer
application data from the database of a service provider to a user’s equipment.
The protocol is structured in a layered manner and employs a general purpose framing system which is
adaptable and extensible, and which carries frames of variable length. This has been designed with the
capability of explicit frame length identification at nearly all levels, giving greater flexibility and integrity, and
permitting the modification of the protocol and the addition of new features without disturbing the operation of
earlier client decoder models.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO/IEC 7498-1, Information technology — Open Systems Interconnection — Basic Reference Model: The
Basic Model
ISO/IEC 8859-1, Information technology — 8-bit single byte coded graphic character sets — Part 1: Latin
alphabet No. 1
ISO/IEC 8859-2, Information technology — 8-bit single byte coded graphic character sets — Part 2: Latin
alphabet No. 2
ISO/IEC 8859-3, Information technology — 8-bit single byte coded graphic character sets — Part 3: Latin
aAlphabet No. 3
ISO/IEC 8859-4, Information technology — 8-bit single byte coded graphic character sets — Part 4: Latin
alphabet No. 4
ISO/IEC 8859-5, Information technology — 8-bit single byte coded graphic character sets — Part 5:
Latin/Cyrillic alphabet
ISO/IEC 8859-6, Information technology — 8-bit single byte coded graphic character sets — Part 6:
Latin/Arabic alphabet
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ISO/IEC 8859-7, Information technology — 8-bit single byte coded graphic character sets — Part 7:
Latin/Greek alphabet
ISO/IEC 8859-8, Information technology —8-bit single byte coded graphic character sets — Part 8:
Latin/Hebrew alphabet
ISO/IEC 8859-9, Information technology — 8-bit single byte coded graphic character sets — Part 9: Latin
alphabet No. 5
ISO/IEC 8859-10, Information technology — 8-bit single byte coded graphic character sets — Part 10: Latin
alphabet No. 6
ISO/IEC 8859-13, Information technology — 8-bit single byte coded graphic character sets — Part 13: Latin
alphabet No. 7
ISO/IEC 8859-14, Information technology — 8-bit single byte coded graphic character sets — Part 14: Latin
alphabet No. 8 (Celtic)
ISO/IEC 8859-15, Information technology — 8-bit single byte coded graphic character sets — Part 15: Latin
alphabet No. 9
ISO/IEC 10646, Information technology — Universal Multiple-Octet Coded Character Set (UCS)
3 Symbols and abbreviations
For the purposes of this Technical Specification, the following abbreviations apply:
3.1
AID
Application Identification
3.2
BPN
Broadcast, Production and Networks (an EBU document publishing number system)
3.3
B/TPEG
Broadcast/TPEG (the EBU project group name for the specification drafting group)
3.4
CEN
Comité Européen de Normalisation
3.5
DAB
Digital Audio Broadcasting
3.6
DARC
Data Radio Channel - an FM sub-carrier system for data transmission
3.7
DVB
Digital Video Broadcasting
3.8
EBU
European Broadcasting Union
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ISO/TS 18234-2:2006(E)
3.9
INV
Introduction, Numbering and Versions (see CEN ISO/TS 18234-1)
3.10
IPR
Intellectual Property Right(s)
3.11
ISO
International Organization for Standardization
3.12
ITU-T
International Telecommunication Union - Telecom
3.13
OSI
Open Systems Interconnection
3.14
RTM
Road Traffic Message application (see CEN ISO/TS 18234-4)
3.15
SNI
Service and Network Information application (see CEN ISO/TS 18234-3)
3.16
SSF
Syntax, Symantics and Framing Structure (this specification)
3.17
TPEG
Transport Protocol Experts Group
3.18
TTI
Traffic and Travel Information
3.19
UAV
unassigned value
3.20
UTC
Coordinated Universal Time
4 Design principles
The following principles have been assumed in the development of the TPEG protocol, structure and
semantics:
— TPEG is unidirectional
— TPEG is byte-oriented, where a byte is represented by eight bits
— TPEG provides a protocol structure, which employs asynchronous framing
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ISO/TS 18234-2:2006(E)
— TPEG includes a CRC error detection capability applicable on a variety of different levels
— TPEG assumes the use of a transparent data channel
— TPEG assumes that underlying systems will have an appropriate level of reliability
— TPEG assumes that underlying systems may employ error correction
— TPEG has a hierarchical data frame structure
— TPEG is used to transport information from database to database
— TPEG provides service provider name, service name and network information
— TPEG permits the use of encryption mechanisms, if required by an application
4.1 TPEG transmission
TPEG is intended to operate via almost any simple digital data channel, and it assumes nothing of the channel
other than the ability to convey a stream of bytes. To this end, the concept of transmission via a “piece of wire”
is envisaged, in which the bearer has no additional service features.
In Figure 1, a variety of possible transmission channels are shown. The only requirement of the channel is that
a sequence of bytes may be carried between the TPEG generator and the TPEG decoder. This requirement is
described as “transparency”. However it is recognized that data channels may introduce errors. Bytes may be
omitted from a sequence, bytes may become corrupted or additional and erroneous data could be received.
Therefore TPEG incorporates error detection features at appropriate points and levels. It is assumed that
bearer systems will introduce an appropriate level of error correction.
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Figure 1 — TPEG data may be delivered simultaneously via different bearers
4.2 TPEG layer model
In Figure 2, the different layers of the TPEG protocol are identified in accordance with the ISO/OSI model
(ISO/IEC 7498-1).
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Figure 2 — TPEG in relation to the ISO/OSI Layer Model
Layer 7 is the top level and referred to in TPEG as the application layer. Initially the following applications
were defined:
— TPEG specifications - Part 3: Service and Network Information Application (Service provider name, logo,
hand-over information, etc.) (CEN ISO/TS 18234-3)
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— TPEG specifications - Part 4: Road Traffic Message application (Event description, location description,
etc.) (CEN ISO/TS 18234-4)
Layer 4 is the packetization layer. Components are merged into a single stream and encrypted and/or
compressed.
Layer 3 is the network layer. This layer defines the means for synchronization and routing. This is the lowest
layer of the TPEG protocol.
Layer 2 is the datalink layer. This layer consists of a wide range of different bearers, which are suitable
carriers for the TPEG protocol. An adaptation layer may be required in order to map the TPEG stream onto
that bearer.
Layer 1 is the physical layer. This defines the transmission medium (radio waves, wire, optical, etc.). One
particular bearer can make use of different physical layers.
5 Conventions and symbols
5.1 Conventions
5.1.1 Byte ordering
All numeric values using more than one byte are coded in “Big Endian” format (most significant byte first).
Where a byte is subdivided into bits, the most significant bit (“b7”) is at the left-hand end and the least
significant bit (“b0”) is at the right-hand end of the structure.
5.1.2 Method of describing the byte-oriented protocol
TPEG uses a data-type representation for the many structures that are integrated to form the transmission
protocol. This textual representation is designed to be unambiguous, easy to understand and to modify, and
does not require a detailed knowledge of programming languages.
Data types are built up progressively. Primitive elements, which may be expressed as a series of bytes are
built into compound elements. More and more complex structures are built up with compound elements and
primitives. Some primitives, compounds and structures are specified in this document, and apply to all TPEG
applications. Other primitives, compounds and structures are defined within applications and are local only to
that application.
A resultant byte-stream coded using C-type notation is shown in Annex E.
5.1.3 Reserved data fields
If any part of a TPEG data structure is not completely defined, then it should be assumed to be available for
future use. The notation is UAV (unassigned value). This unassigned value should be encoded by the service
provider as the value 00 hex. This allows newer decoders using a future TPEG specification to ignore this
data when receiving a service from a provider encoding to this older level of specification. A decoder which is
not aware of the use of any former UAVs can still make use of the remaining data fields of the corresponding
information entity. However, the decoder will not be able to process the newly defined additional information.
5.2 Symbols
5.2.1 Literal numbers
Whenever literal numbers are quoted in TPEG specifications, the following applies:
123 = 123 decimal
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123 hex = 123 hexadecimal
5.2.2 Variable numbers
Symbols are used to represent numbers whose values are not predefined within the TPEG specifications. In
these cases, the symbol used is always local to the data type definition. For example, within the definition of a
data type, symbols such as “n” or “m” are often used to represent the number of bytes of data within the
structure, and the symbol “id” is used to designate the occurrence of the identifier of the data type.
5.2.3 Implicit numbers
Within the definition of a data structure it is frequently necessary to describe the inclusion of a component
which is repeated any number of times, zero or more. In many of these cases it is convenient to use a
numerical symbol to show the component structure being repeated a number of times, but the number itself is
not explicitly included within the definition of the data structure. Often, the symbol “m” is used for this purpose.
6 Representation of syntax
6.1 General
This section introduces the terminology and the syntax that is used to define TPEG data elements and
structures.
6.2 Data type notation
A data type is an interpretation of one or more bytes. Each data type has a structure, which may describe the
data type as a composition of other defined data types. The data type structure shows the composition and
the position of each data element.
TPEG defines data structures in the following manner:
:= : Description of data type
(optional symbol),
: Component description
(optional symbol); : Component description
This shows an example data structure, which has just two components, one of type and
the other of . A symbol may be assigned to the data type, to relate the element to
another part of the definition. Comments about the data structure are included at the right-hand side
delimited by the colon “:” separator. Each of the constituent component data types may be itself
composed of other data types, which are defined separately. Eventually each data type is expressible
as one or more bytes.
Where a component structure is repeated a number of times, this may be shown as follows:
:= : Description of data type
, : Component description
m * ;
: Component description
Often, in such cases it is necessary to explicitly deliver to the decoder the number of times a component
is repeated or the overall length of a data structure in bytes. Sometimes it is not.
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Where the number of repetitions must be signalled, it may be accomplished using another data element as
follows:
:= : Description of data type
(n), : An integer representing the value of "n"
n * ,
: Component description
; : Component description
In the above example a decoder has to have the value of “n” in order to correctly determine the position
of .
In this example the decoder uses the value of “n” to determine the overall length of the component data, and
the value of m is determined implicitly:
:= : Description of data type
(n),
: Length, n, of component data in bytes
m * ; : Component data
This data type definition is used to describe a variable structure switched by the value of x:
:= : Description of data type
(x),
: Select parameter, x
if (x=1) then , : Included if x equals 1
if (x=2) then , : Included if x equals 2
A hypothetical example serves to illustrate the basic TPEG notation concepts:
:=
: School data
(n), : Number of children in school (n)
n * ; : Data about children
:= : Information about a child
,
: Height in cm
, : Weight in kg
; : Age in years
:= : An integer in the range 0.255
; : Primitive element
6.3 Application independent elements
This section describes the primitive elements and compound elements that are used by TPEG applications.
6.3.1 Primitive elements
The fundamental data element in TPEG technology is the byte, which is represented by 8 bits. All other
primitive data types are expressed in terms of bytes as follows:
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6.3.1.1 Basic numbers:
:= : Integer Unsigned Tiny, range 0.255
; : Primitive
:= : Integer Signed Tiny, range -128.(+)127
; : Two's complement
:=
: Integer Unsigned Little, range 0.65 535
, : MSB, Most Significant Byte
; : LSB, Least Sign
...
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