PARK RIDGE, Ill. An auto industry consortium plans to decide in the next few weeks whether to endorse two high-speed electrical buses for multimedia applications.
The Automotive Multimedia Interface Consortium (AMIC) will release the draft of a specification late this summer that includes an endorsement of a low-speed bus and possibly endorsements of one or two high-speed buses. The proliferation of electronic devices requiring greater bandwidth, such as navigation systems, cell phones, digital radios, in-car PCs and video screens, is pushing the need for a high-speed bus in future vehicles.
The two high-speed buses at issue are the Media Oriented Systems Transport (MOST) and Intelligent Transportation Systems Data Bus based on the IEEE 1394 spec (IDB-1394). While both buses offer high data transfer rates of up to 24.8 Mbits/second, they remain unproven and surrounded by problems involving intellectual property.
"Right now it appears that neither MOST nor 1394 will be ready for 'release one,' " said Russ Shields, executive director of AMIC. "We might have to defer the decision to endorse one or both of those until the second release." The second release of the specification is expected by 2002.
"It's not completely clear yet if any high-speed bus will be adopted," said Scott Andrews, a former Toyota engineer and founding member of AMIC. "That still needs to be decided." Some members of AMIC's steering committee, however, still hold out hope that one or both of the buses will be endorsed in the first draft.
Endorsement by AMIC is a significant step forward for any of the bus technologies, given that members of the consortium include 12 of the world's biggest automakers: BMW, DaimlerChrysler, Ford, Fiat, General Motors, Honda, Mitsubishi, Nissan, PSA/Peugeot-Citroen, Renault, Toyota and Volkswagen.
The consortium has two reasons for pursuing a standardized bus structure: First, automakers need network buses if they plan to reduce the thickness of wiring bundles in today's vehicles.
Second, they need standard architectures so they don't have to reengineer vendor products. Automakers complain that in the re-engineering process they lose valuable months or even years adapting products that are not created to any specific standard.
In the first release of the specification, which is already said to be about 400 pages long, AMIC said it will endorse one bus, Intelligent Transportation Systems Data Bus-CAN (IDB-C). That bus is based on the controller area network (CAN) specification originally developed by Robert Bosch GmbH. CAN buses have been used in the auto industry since the mid-1990s. At operating speeds of about 250 kbits/s, however, they are far slower than the high-speed buses.
High-speed buses, though, don't have CAN's successful track record in automobiles which is why some AMIC members hesitate to forecast endorsement in the first release of the spec. "AMIC's charter doesn't call for us to endorse a technology based on its potential," Shields said. "First, we want it to be out there in a car to see how well it works."
In the case of the IDB-1394 bus, a proven record of success would go a long way toward its adoption. Engineers question whether IDB-1394 meets the electromagnetic interference conditions needed for an automotive environment.
The larger issue for some automakers, however, is intellectual property. Implementers of some potential automotive technologies, such as MOST, must sign a cooperative agreement. AMIC committee members claim that those agreements typically include nondisclosure clauses restricting users from discussing proprietary details of the technology with other companies.
According to automakers, that flies in the face of AMIC's written charter, which calls for open specifications. "For any bus spec to be adopted, it needs to meet certain criteria," Andrews said. "It needs to be open; it needs to be publicly available and it needs to be something we can build against."
AMIC members claim it's unlikely that every potential user of the MOST technology will want to sign the required licensing agreement. And if vendors are unwilling to sign such agreements, then the technology won't be adopted soon. "If I'm restricted from talking to people who haven't signed the nondisclosure agreement, it makes implementation of the technology very, very difficult," Andrews said. "Until it's truly open, that adds a whole level of restrictions. It makes it very difficult for us to walk in with our eyes open and adopt it."
Members of the MOST Cooperation contend that their specification is open to members and nonmembers alike. This past week, MOST released an official statement saying that the spec is available on the MOST Web site. Henry Muyshondt, general manager for business development for Oasis SiliconSystems AG (Austin, Texas), one of the founding member companies of MOST, said, "There are some subsystems that are still being worked on, and those are not yet publicly available. Over time, all the specs will become available as the technology is proven out."
The MOST Cooperation consists of three types of members: foundation partners, including Oasis SiliconSystems, DaimlerChrysler, BMW and Harman/Becker; so-called "A" partners, all of which are automakers; and "B" partners, including 42 vendors. All members have the same right to use the technology, but higher-level members have more say in the consortium's technological direction.
"Signing our agreement only means that you will help further the MOST technology," Muyshondt said. "You have to agree not to assert any intellectual property rights that will block our technology from going forward."
The MOST partners hope that the availability of the standard on their Web site will help convince AMIC to endorse it in the first release of the spec. "Individual AMIC members have mentioned a concern with legal issues," Muyshondt said. "But AMIC as an entity has not communicated any problems to MOST."
Ideally, AMIC members said they would like all technologies to be as open as the IDB-C bus. The IDB-C bus specification is easily available through the Society of Automotive Engineers. "You don't have to sign your life away just to get a copy of the spec," said one engineer who asked not to be named. "It's true that you have to pay a licensing fee for a chip you get from Bosch, but the specification is publicly available."
AMIC members, however, still worry that endorsement of a technology that isn't open compromises their charter. "The worst thing for us is to be perceived as an exclusive club," said Dave Acton, chief vehicle engineer for OnStar, and a member of the AMIC steering committee. "AMIC is, first and foremost, about commonizing requirements. And once we commonize the requirements, that serves as an enabler to a standard."
AMIC members agreed, however, that they are less concerned about MOST's licensing fees than they were two months ago. Some members initially believed that the 30-cent bus-connection fee MOST requires was unacceptable. But seeing the potential importance of the technology, many said they will now pay the fee if they have no alternative. "If our needs are such that 30 cents per connection is a bargain, then we'll go for it," Acton said.
Ultimately, the key to success for any high-speed bus maker is a willingness to work with others. The process of endorsement starts with a set of requirements put forth by AMIC, followed by give-and-take between the bus supplier and the consortium. "The main thing we're looking for is an attitude that says, 'We're willing to work with you,' " said Acton.
High-speed bus suppliers with the right attitude could see acceptance either in the first or second release. "The question is still: Can we resolve the issues for the first release?" Andrews said. "We're working on putting the high-speed buses in there, but they are not now part of it. And unless we can resolve the issues, they'll have to wait for subsequent releases."