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Automotive Industry in
Europe Takes the Lead in
the Introduction of Optical
Data Buses
US and Japanese Suppliers React with a Higher Speed Concept
Impact on the Wire Harness Business
By Paul Polishuk, President
Information Gatekeepers, Inc.
Introduction
Automobile manufacturers worldwide have discussed the potential of using
optical data buses in autos for over a decade. Until recently, the only
application of fiber optics were simple, low speed, point-to-point links and
lighting applications. With the increased demand for multimedia digital
applications in autos similar to that in homes, auto manufacturers are faced
with a dilemma. To meet the needs of multimedia, additional high-speed
wiring is required. Existing copper cables suffer from a number of deficiencies
such as added weight, complexity, cost, and susceptibility to EMI. Realizing
that the time had come to take a drastic look, the European auto manufacturers,
led by Daimler Benz, have decided to take a dramatic new approach and introduce
a digital data bus standard called MOST, which operates at 24 Mbps over plastic
optical fiber.
Not to be outdone, the US and Japanese auto manufacturers have analyzed the
MOST standard and concluded that 24 Mbps speed being implemented by MOST
was far too conservative to meet future needs and is now developing a separate
standard that will operate at 400 Mbps. This paper reviews the progress being made
by the MOST Cooperation and the plans of the US and Japan auto manufacturers.
What is MOST?
MOST (Media Oriented Systems Transport) is the title of a joint venture between
auto OEMs, systems suppliers, and equipment manufacturers in their quest for a
common goal: develop a standard for an onboard multimedia network protocol
and network model.
When did it get started?
It was back in 1998 that "MOST" was born. The initial members were BMW
and DaimlerChrysler, Straubing-based audio and multimedia specialist Harman
Audio Electronic Systems and Becker GmbH Automotive Systems of Karlsbad,
along with systems designer Oasis Silicon Systems AG of Karlsruhe.
Since then this worldwide joint venture has grown to include 20 motor manufacturers
and 60 systems suppliers, designers and equipment manufacturers (see table). All of
them have contributed their knowledge and skills in order to develop, establish and
refine a standard for the multimedia networks now making their appearance in motor
vehicles.
In order to meet complex requirement profiles, a solution was needed which
addresses the specific problems to be encountered on board an automobile. In
other words, nothing short of a "revolutionary evolution." The search was on for
a high-performance multimedia network which could stand up to the high cost
pressures applied by the OEM's, satisfy the demand for quality refinements and
reductions in weight and size, and at the same time accommodate a flood of new
applications.
A uniform structure can only be created by digitizing all on-board applications.
Digitization alone, maintained the MOST spokesman, provides the necessary
homogeneous structure on which to base the successful integration of multimedia
network systems.
Separating network and application
An essential aspect in the definition of MOST was the clear separation of network
and application. In the way future generations of this technology can be developed
to meet increasing demands and achieve further reductions in cost without the need
to change the applications layer.
There are essentially two main elements which comprise MOST technology:
the MOST network layer and the MOST applications layer. The first has a
bandwidth of 22.5 Megabits per second and allows multimedia services of all
kinds to be transmitted via a single POF (polymer optical fiber).
Part of the partners' task is to lay down common fiber solutions, plug connections
and optical transmitters/ receivers. Common definitions for transport layers and
network management have already been developed and integrated into a standardized
network software solution. The MOST members are also working on common access
mechanisms, firewall techniques and diagnostic services.
The applications layer offers an object model for system management. This
comprises clearly structured, flexible and scalable system architectures with
"plug-and-play" characteristics. Common "Application Programming Interfaces"
(API's) have been defined for standard equipment such as amplifiers, DVD players,
television receivers, telephones and Web browsers and other Internet applications.
It is also intended to standardize the methods by which information on the body shell
and engine control system can be accessed. The following principal objectives formed
the basis for the MOST system architecture:
• Availability for consumer applications with or without a
central PC as a control unit.
• Low-cost solutions with data transfer rates of up to 24 Megabits per second with growth potential for 150Mbps/
• System to be optimized for fiber optics.
• Simplicity of use combined with excellent reliability.
• Full support for real-time audio and video applications including compression.
• Synchronous and asynchronous data transmission.
• An open protocol interface which permits the use of a variety of different protocols.
• Integration of virtual network management.
• Integration into everyday technical equipment.
• Broad-based availability of essential components.
• Scalability at equipment level.
• Equipment specification to be such as to guarantee problem-free implementation.
• Maximum transparency of all network functions.
But that's not the end of the story: the next generation of the MOST network layer
is already being developed and is expected to bring even higher efficiency and
greater bandwidth, along with new performance features. "The MOST venture is
collaborating with international Standards bodies and organizations including
"AMIC," "ERTICO," "IDB," "ITS," and "ISO" with the object of creating a
worldwide standard for in-car multimedia communications."
Status of the MOST Standard
The MOST Specification 2.1 was published in 2001 and is available on the MOST
Cooperation web site at www.mostcooperation.com. In March of 2001, the MOST
Cooperation published an update to the original specification. The revisions included
four major areas:
• MOST Physical Layer Specifications Rev 1.0: detailing electrical and optical
requirements of the physical layer as well as the mechanical details of standard
connectors.
• MOST High Protocol Specification Rev 2.1: detailing how data is transmitted
over the control and asynchronous channels of the MOST network.
• MOST Content Security Specification Rev 1.0: detailing the protected and
controlled distribution of digital content over the MOST network especially
used for DVD.
• MOST Content Protection Scheme: DTCP Implementation: detailing the
functions and services required to enable Digital Transport Content Protection
(DTCP) protocols over MOST.
Intellectual Property
Initially, the MOST Cooperation had set the license fee at a maximum of
0.3 Euro per device. Since then, the group has been working to reduce the fee
in order to support global distribution of the technology. MOST moved in that
direction in May 2000 when it made various specifications publicly available.
Since then, the founding partners (Audi, BMW, DaimlerChrysler, Harman/Becker
Automotive Systems and Oasis SiliconSystems) have cleared the way to make
the MOST System technology royalty free.
The decision takes a significant step toward MOST's goal of globalizing the
automotive standard, which is designed to offer full interconnectivity for
in-vehicle audio, video and data services over a plastic fiber optic network.
Status of MOST Applications
The status of the MOST system is best exemplified by demonstrations of two
major automobile trade shows, one at the International Transportation Systems
(ITS) World Congress in Turin, Italy in November of 2000 and second at the
2001 SAE World Congress in Detroit, Michigan in March 2001.
At ITS - Turin, 6 car manufacturers showed their clear commitment in using
a common multimedia and telematics in-car network architecture based on
the MOST standard.
Audi (A8), BMW (X5), DaimlerChrysler (S-Class) and Volkswagen (New Beetle)
demonstrated their cars equipped with the MOST technology at the booth of the
MOST Cooperation. MOST is gaining acceptance in all segments of the automotive
industry, starting with high-end luxury sedans and sporty SUV's, moving over time
to mid- and low-end cars.
Fiat and Ford (Lincoln and Jaguar) also demonstrated cars based on the
MOST technology at their booths.
Applications shown included audio and video for rear-seat entertainment, internet
access and "mobile office" computing, navigation and telematics. The demonstration
also showed how MOST allows components from different manufacturers to be
interchanged.
Carmakers benefit from being able to choose devices from a broad group of
suppliers. They can match the best components from each supplier to create a
superior system.
Suppliers benefit by being able to sell their products to all car makers without
having to customize the interface to each car network.
2001 SAE World Congress
The MOST Cooperation showed off its latest technology during the 2001
SAE World Congress in Detroit, Michigan. A Chrysler Town & Country
minivan and a BMW X5 sport utility vehicle were on display to showcase the
latest in high-speed fiber optic networking for automotive applications. An
Audi A8 was also described in the booth that incorporates a multi component
MOST network. The main message was that MOST is now being put into production
vehicles. It has become the high-speed
network of choice to encompass all of today
and tomorrow's entertainment, multimedia, telematics and data services that are
needed in the automobile. It is cost-effective by allowing different functions to be
easily connected together over inexpensive plastic optical fiber. Development costs
are also reduced when all devices use a common hardware and software interface.
The Chrysler Town & Country included two DVD players, a CD changer, a radio
and a power amplifier, all integrated together into a rear-seat entertainment system.
Passengers could enjoy DVD movies and high quality audio over an easy-to-use
system. The overhead video display provided a crisp clear picture while the
touch-screen user interface allowed for intuitive control of the various
system functions.
The BMW X5 sported two video displays for the rear-seat passengers and
video cameras in the front bumper that showed obstacles when the turn signal was
activated. Each passenger could enjoy his choice of a movie. A navigation system
and telephone were seamlessly integrated into the system. MOST defines the
functions necessary for al these systems to interoperate. Driver safety is increased
as all the parts of the system are easily controlled to reduce driver distractions.
For example, the audio system can automatically mute when a phone call is
answered. The system has a hands-free speakerphone so the driver does not
need to take her hands off the wheel.
Yazaki North America demonstrated a MOST ring playing multiple
simultaneous MPEG movies. The system also had a MOST to CAN
Bluetooth interface that showed Bluetooth devices interacting with MOST
devices. An analog gateway brought analog audio and video into the system
and connected to a Personal Digital Assistant (PDA) device.
Is the Market for MOST Real?
It is difficult to assess the market for MOST at this time since numbers are
not readily available. However, here are some numbers obtained in interviews
with DaimlerBenz (DB) employees in March of this year:
a. MOST had its origination in the D2B system, an audio system for high-end
Mercedes Benz cars. The D2B system using plastic optical fibers was first
introduced into the E,C,A, and M classes.
b. DaimlerBenz (DB) manufactures approximately one million Mercedes-Benz
passenger cars per year, most of them are supplied with a D2B system.
c. Beginning in 2002, DB will introduce the MOST system in the new E-class,
one of DB's large volume markets.
d. It is very likely that step-by-step the D2B system will be replaced by
MOST in all DB passenger cars.
e. Other manufacturers are introducing MOST in 2001-2002 models. For
example, BMW started in 2001 in the new 7er series. BMW also plans to
install a second POF-based data bus system, the so-called ByteFlight Data Bus.
A concluding anecdote is another indicator that the market for MOST is real.
The author was attending a meeting at a local hotel recently where a sales
training session was being organized for MB dealers in the Northeast US.
The chief trainer was asked if he had heard of the use of POF in MB autos.
The author was astounded to hear the detail that the trainer started to explain
how POF was going to replace copper wires in all future MB cars and the
reason being it was more economical, less susceptible to EMI, etc. It was
like turning on a faucet and getting more water than could be handled.
US and Japanese Auto Manufacturers Response to MOST
At the 1394 Developers Conference held this past August 2001 at Microsoft's
Executive Conference Center in Redmond, Washington, several papers were
presented describing the 1394 Trade Association's efforts to develop a new
1394b standard for autos. The rationale given to use 1394 in autos was the following:
• Consumers want the same amenities they have in the home in the family car
• 1394 has well defined protocols and models
• Silicon and firmware availability
• Market established and growing fast
• The new 1394b specification provides the needed improvements
for the auto environment
- Longer distance (10 meters vs. 4.5 meters)
- Noise immunity and isolation (fiber and transformer isolated copper)
Adapting 1394 to Automobiles
The work on the 1394 specification modification for auto use is being done
primarily by the 1394 Trade Association's Automobile Working Group
"1394 AuWG," chaired by Brad Little of Texas Instruments and co-chaired
by Frank Desjarlais of the Ford Motor Company. The initial work on the POF
media, connector and power management has already been completed by a
connector group including MOLEX, SEI, Delphi and FCI.
Figure 1 describes the 1394 AuWG development process.
1394 AuWG Requirements
• All link, transaction, and bus management layers shall be the same as
defined in IEEE1394.
• All nodes shall be cycle master capable.
• All nodes shall be isochronous resource manager capable
• The cable and connectors shall be S400 capable
• The connection system must be able to support 10 meters and two in-lines
• All applicable automobile ruggedness, emissions and susceptibility
requirements must be met
• Embedded devices shall support S100, S200, or S400 operation.
• All devices shall use the IDB-1394 automotive connectors
• The connection system must be able to support 10 meters and two in-lines.
• Maximum number of embedded devices is 63 nodes.
Automotive Architecture Model
The following figure shows the architecture of 1394 automotive vehicle systems.
This auto system includes mission critical and non-mission critical functions.
1394 is standard for the non-mission critical aspects. The median being proposed
includes both POF and copper. The other automotive architecture figure shows an
implementation using POF and copper. The customer convenience port (CCP)
allows portable consumer electronic devices to be put in or taken out.
(See figures 2, 3 and 4)
Major New Changes Required by the 1394 Specification
In order to adapt the 1394 Specification to autos, the following changes
are required:
• All link, transaction, and bus management layers shall be the same as
defined in IEEE1394.
• Serial bus management shall be the same as defined in IEEE1394.
• All nodes shall be cycle master capable.
• All nodes shall be isochronous resource manager capable
• The cable and connectors shall be S400 capable
• Embedded devices shall support S100, S200, or S400 operation.
• All devices shall use the IDB-1394 automotive connectors
• The connection system must be able to support 10 meters and two in-lines.
• Maximum number of embedded devices is 63 nodes.
History of the Automobile Multimedia Data Bus
Over the past 18 months, the 1394 Automotive Working Group (1394 AuWG)
founded in January 2000, has led the charge in developing a 1394 automotive
specification that will allow 1394 to be used as a multimedia bus in a vehicle.
The 1394 AuWG is not the first attempt to develop a multi-media bus for
automobiles. The following is a short listing of the developments of a
multimedia Vehicle Databus:
• Automotive manufacturers (worldwide) have been trying to standardize on
"ONE" multimedia bus for in-vehicle use since 1996.
• ERTICO established "Car Multimedia Open Bus Architecture" Committee
Candidate buses: D2B, MML, HiQOS, MOST, FireWire (1394). Were not
able to make a decision on one bus standard and did not receive funding to
continue their work.
• IDB Forum was formed in 1999 to continue the work beginning where
ERTICO left off. Currently has >70 members ranging from automotive
suppliers to consumer electronic companies such as Panasonic.
• AMIC was formed in 1998 (~ 60% of the worldwide vehicle manufacturers).
- Demonstrated 1394 technology at Convergence 2000
• 1394 TA and the IDB Forum formed a joint working group to develop
the automotive 1394 specification (IDB-1394) by December 31, 2000.
- Draft 1.9 (Physical Layer) completed July 28, 2000.
- PM draft 1.0 completed June 30, 2001.
• In the past, concerns about EMI has made plastic optical fiber (POF) the
transport media of choice in the vehicle for high speed buses.
• Recent discussions and studies have generated a significant interest in
evaluating the suitability of using unshielded twisted pair UTP5 in the
vehicle at 100 Mbps.
• It is likely that the multimedia bus of the future will be a hybrid and
use both copper and fiber as the transport media.
Cost is King!
The key reason for a standard approach to a vehicle data bus is cost.
Reasons given for factors driving cost include:
• A proprietary bus increases costs
• Automotive manufacturers want economics of scale
• Automotive manufacturers want dual sources of supply.
First Demonstrations of 1394 for Auto
The first demonstrations of the applications of 1394 in an auto was at
Convergence 2000 in Detroit and the Consumer Electronics Show (CES)
in Las Vegas, the same year. No US or Japanese manufacturers have yet
announced any 1394 Auto products. The following is a schedule planned
for development of IDB - 1394 specification.
1394 AuWG schedule
• IDB-1394-1 Automotive Physical Layer Specification – Completed, 3/01
- 100Mbps POF Physical Layer, Connectors & FOT - Completed, 3/01
- Power Management – Completed, 7/01
• IDB-1394-2 Automotive Message Sets
- Multi-media message set - Completed
- Multi-media message set GAP analysis - 2Q/01
- Automotive specific message sets – 3Q/01
• IDB-1394 (1394b) First Pass Automotive Silicon – 3Q/01
• IDB-1394 (1394b) First Pass Automotive 100Mbps FOT – 3Q/01
• IDB-1394 (1394b) Automotive Unshielded Twisted Pair – CAT5
- Prototype demo – Available today
- Silicon – Same silicon as POF – 3Q/01
- Finalized, validated automotive cable/connector specification – 4Q/01
• IDB-1394 200Mbps POF – 1Q/02
• IDB-1394 400Mbps POF – 3Q/02
How will IDB-1394 and MOST Co-Exist?
The MOST standard is well-developed and is well along in its implementation
on a wide variety of European autos. Suppliers are already developing products
and moving down the learning curve. IDB-1394 is still in the development
stage and probably won't be ready for prime time for at least another year. It is
not clear yet that any US or Japanese auto manufacturers have committed to the
standard. It is also not clear whether the higher speed claimed by the 1394 TA is
really needed. It won't be determined until it is introduced consumer interest is measured.
It is clear, however, that each group will learn from each other as to how the
systems are used and/or adapted by the users. In either case, the need for
automobile wiring will significantly change, requiring new skills and cost
structures. The market for POF and components will get a major boost no
matter which standard prevails.
For further information on the 1394TA AuWG, IDB-1394,
the Future Automative Multimedia Bus, see: www.1394TA.org
For the MOST Activity, www.mostcooperation.com
For further information on 1394 and POF, see Information Gatekeepers'
web site at www.igigroup.com Contact IGI Consulting Inc.
214 Harvard Ave. Suite 200, Boston, MA 02134.
E-mail: ppolishuk@igigroup.com
Editors Note: For a complete reprint (charts/graphs included) please contact: marilyn@wiringharnessnews.com
Or download the complete PDF file. (Adobe Acrobat Required)
Optical_Data_Buses.pdf
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