New Standards-based Network Topologies Enable Innovative In-Vehicle Entertainment, Navigation, Capabilities 

by Akio Nezu, Fujitsu Microelectronics America

ec92if100aDespite recent economic challenges facing the auto industry, many leaders are moving forward with new and innovative systems for in-vehicle entertainment, and sophisticated audio-video capabilities.  Industry analysts such as iSuppli Corporation have cited significant consumer demand for audio-video connectivity and networking in the vehicle, noting that the industry is at a point where A/V connectivity clearly influences sales. Rear-seat entertainment systems, as shown in Fig. 1, are on their way to becoming a standard feature in a wide range of vehicle models.

In today’s economy -- where research and development investments are difficult to justify and long life cycles for electronic technologies are mandated -- a standards-based approach saves time and cost, while providing optimal flexibility.  The 1394 Automotive network, developed based on the popular FireWire standard, offers an excellent solution for in-vehicle electronic applications. Whether the platform is an entry level or a luxury model, the same technology is shared and is expandable -- even at the dealer level. The 1394 Automotive technology was created by automakers and component companies with baseline requirements for today’s automobile, and it meets the demands of global leaders such as Nissan, Honda, Ford and others.

ec92if101aThe car companies were explicit in their base requirements. First, they prefer a mature, proven network technology with data security and content protection that ensures that copyrighted music and video are secure while moving around the network. The 1394 standard is long proven in terms of content protection in consumer electronics, and brings the same advantage to the automobile. The DTLA (Digital Transmission Licensing Administrator) has endorsed 1394 for content protection.  Along with a proven technology, the automakers want a cost-effective and viable forward-looking roadmap so they can implement another significant industry trend – the ability to invest in a technology that will scale forward in future model years.  The 1394 Automotive standard meets that requirement, starting at 400-Mbps speeds, and the 400 Megabit/second and 800 Megabit/second versions of 1394 Auto are available shortly. Faster, backwards-compatible implementations are in the road map and already being developed.

The car companies worldwide also require a highly cost-effective, reliable networking technology that can be used in long term design cycles, up to 12-15 years or even more.  Cost is of primary importance. Many factors such as the number of silicon players, maturity in a technology base, harness flexibility and licensing fees come into play in understanding applied cost. 1394 Auto benefits from synergistic deployment in the computer and entertainment space that continues to drive down silicon costs. There are 1394-based industrial control cameras and hard disk drives that can be adapted for use in autos without significant effort once the 1394 standard moves into those applications. All of the connector and automotive harness systems that are part of the network topology as illustrated in Figure 2 selected for 1394 Auto will be shipping worldwide with multiple sourcing.

ec92if102aAmong other advantages is the minimum bit rate of 400 Megabits/second, higher than any alternative standard, including MOST – the Media Oriented Systems Transport standard that is used in some European models.  In addition, there are 800 Megabit/second devices coming to the market, providing the scalability and versatility important to the carmakers, while preserving the value of 1394-equipped product investment as speed and bandwidth increase.

Additionally, 1394 Auto offers a very flexible interconnect, allowing for bus, star, ring, daisy chain, tree, and other topologies. The automotive engineer can mix and match topologies, even connecting 1394 Auto in a ring for fail-safe operation that will survive any single cable or device fault.   Because 1394 can be configured as a multiplexing network, multiple video and audio streams can be transmitted simultaneously over the same physical layer. As a result, the vehicle network can carry complex information over a single cable, reducing wiring-harness complexity and weight.

With 400 Mbps now available for audio and video transmission over either copper or plastic fiber around the car, truck or SUV, the network can link multiple communication channels on one wire harness. The 1394 standard enables many audio streams of compact disc audio along with multiple streams of DVD.

Closed area implementation may vary, and may be different for different consumer application cases. But the network can easily include DVD players, PCs, handheld products, games and other peripherals -- and 1394 allows multiplexed transmission of audio and image content, that are divided and transmitted simultaneously on different channels.

Fujitsu Microelectronics has developed a 1394-compliant controller series to meet the requirements of the standard in an efficient, compact and cost-effective single chip solution.  It incorporates both physical and data link layers in one sliver of silicon, just for these rear-seat entertainment systems.  The newest member of this family is the MB88388A, which supports the initial 400 Megabits/second data rate.  Faster versions are now under development.
This controller also complies with the DTCP, which pre-empts illegal copying, and supports BT.601  (a video signal standard) compressed video on the 1394 protocol.  The Fujitsu BT.601 video interface and I2S interface includes streaming capability.  By reducing the host processor's overhead, this kind of device lets system designers deliver an efficient video and audio network system without the cost of the host processor -- or by using an existing host processor to handle 1394 controller with minimum overhead.

Another feature important to successful A/V streaming in the network is the Fujitsu SmartCODEC, a video codec that can transmit compressed digital video without perceptible latencies. It is designed to be sure that there are no multiple video stream bottlenecks in the 1394-based system.

In addition to these devices, the 1394 Automotive specification has been moved forward to prototyping by a new coax standard that automakers deemed an important requirement. 

Completed last fall, the 1394 Copper Automotive Standard allows for networks built on a number of cable/connector systems, including “Shielded Twisted Quad” (STQ), “Shielded Twisted Pair” (STP) and single COAX operating in full duplex mode.   In addition, a new optical standard based on Hard Polymer Clad Fiber (HPCF) was established for faster optical network for 1394 standard that delivers speed and lighter cable apparatus for automobile applications. Those new technologies meet the requirements of the automakers, and reinforce the trends toward more electronics and deployment of in-vehicle entertainment and navigation networks. Prototyped systems are now being implemented, and will move into pre-production this year and throughout 2010.

Akio Nezu, senior manager for the Automotive Business Group at Fujitsu Microelectronics America, Inc., has been a leader of FMA's embedded products group for several years. For more information, call 408-737-5600, e-mail, or go to