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An Architecture for In-Vehicle Infotainment Systems


Manageability

The manageability or device management (DM) framework provides services on the client platform, for use by IT personnel remotely. These services facilitate the key device management functions like provisioning, platform configuration changes, system logs, event management, software inventory, and software/firmware updates. The actual services enabled on a particular platform are choice for the car OEM.

Open Mobile Alliance - Device Management (OMA-DM) is one of the popular protocols that would allow manufacturers to cleanly build DM applications that fit well into the IVI usage model. Many of the standard operating systems support OMA-DM or a variation of it with enhanced security. The data transport for OMA-DM for the Intel-based IVI platform is typically over wireless connectivity like WiMax or 3G/4G. This protocol can run well on top of the transport layers like HTTPS, OBEX, and WAP-WSP. The Intel-based IVI platform would be able to support this, as long as the OEM supports the connectivity and the client services. One of the limitations of OMA-DM is that the Intel-based IVI platform is fully powered with the DM client services activated on top of a fully functional OS.

The other possible framework for manageability is Intel Active Management Technology (Intel AMT). Intel AMT provides full featured manageability that can discover failures, proactively alert, remotely heal, recover, and protect. Intel AMT Out of Band (OOB) device management allows remote management regardless of device power or OS state. Remote troubleshooting and recovery could significantly reduce dealer service calls. Proactive alerting decreases downtime and minimizes time to repair.

In the manageability space, making Intel AMT available on the Intel-based IVI platform is an opportunity that allows car OEM differentiation and provides a much richer manageability features. This is also an opportunity for IHVs/ISVs to pursue, while research into retrofitting OMA-DM with the benefits of the Intel AMT features on the part of academia would be welcomed to enable Intel AMT on the current generation the Intel-based IVI platform with limited to no hardware changes.

In-Car Connectivity

The rising popularity of passenger entertainment systems and cameras in and on the car places an increasing burden on the car's network infrastructure to transport large amounts of high-bandwidth, low latency video and audio data between built-in devices such as the head unit, DVD players and changers, cameras, rear-seat entertainment system, amplifiers, speakers, and remote displays. Legacy in-car connection technologies such as CAN, LIN, and Flexray are cost-effective and well-suited for messaging between engine control units (ECUs) in the car, but these technologies lack the necessary bandwidth to distribute video content. Blu-Ray video, for example, requires up to 54 megabits per second of bandwidth, well above the capability of legacy car networks. Technologies that have been explored for interconnectivity of in-car multimedia devices include MOST, Ethernet, and IDB-1394. MOST and Ethernet will both be enabled by the Intel-based IVI platform.

MOST

Currently, the leading in-car multimedia transport technology is Media Oriented Systems Transport (MOST). MOST requires each device in the network to be equipped with a MOST Network Interface Controller (NIC). MOST is a circuit-switched, time-domain multiplexed network technology that enables the transfer of digital audio, video, data, and control information between multiple networked devices. MOST scales in bandwidth from 25 Mbps (MOST25) up to 150 Mbps (MOST150). MOST150 is capable of transferring content at 150 Mbps over a polymer optical fiber (POF) wire harness. In addition to higher bandwidth, MOST150 features new isochronous transport mechanisms to support extensive video applications, as well as an Ethernet channel for efficient transport of IP-based packet data. MOST has a strong presence in automotive and many multimedia devices currently support MOST, so its popularity in high-end cars is not expected to diminish in the foreseeable future. The Intel-based IVI platform with the Intel Atom processor will feature a glueless, high-bandwidth dedicated interface to a MOST Intelligent Network Interface Controller (INIC). Drivers and a MOST protocol stack will also be available to enable MOST integration.

Ethernet

While the synchronous nature of MOST makes it ideal for transporting high-bandwidth, low-latency multimedia traffic between endpoints in a network, nothing surpasses Ethernet networking in terms of its raw bandwidth, cost, extensive ecosystem, hardware availability, and software support. Historically, Ethernet has been used in the car strictly for diagnostic services and software updates. Ethernet cost-effectively scales up to 1 Gigabit per second, which allows large amounts of data exchange between the service infrastructure and the car. However, Ethernet quality of service (QoS) mechanisms have been inadequate for distributing low-latency, jitter-free synchronized audio and video traffic throughout the car. For example, if the car's head unit is distributing multiple channels of audio to network attached speakers and synchronized video to a network-attached display, the speakers and the display must share a common clock in order to prevent speaker channels from drifting apart and to maintain lip synchronization between the audio and video. Some new techniques being proposed by the recently-formed 802.1 Audio/Video Bridging (AVB) Task Group promise to provide time-synchronized low latency streaming services over Ethernet could address this shortcoming. Some car OEMs are also performing trials to explore data transport of IP over Ethernet with QoS mechanisms implemented in the IP layer. Still, AVB is likely to become the most cost-effective and efficient solution for audio and video streaming over Ethernet. The Intel-based IVI platform with the Intel Atom processor will include an Ethernet controller that includes support for AVB with a clock output pin to drive an external audio clock.

In-Cabin Connectivity (Car-to-Portable Device)

The demand for on-the-go access to audio/video content and information has exploded over the past few years. Consumers are increasingly consuming content on the go through iPods and portable multimedia players. Having a multimedia-capable platform in the car offers an opportunity to bring portable content in the car and use the high-quality displays, sound systems, and controls of the car to render that content in a more enjoyable way. Historically, portable devices have been connected to the car primarily through a USB port or a proprietary wired analog interface. An increasing number of devices now include wireless interfaces that enable devices to stream content to the car with more quality and less effort by the consumer. Bluetooth also enables hands-free cell phone operation. The Intel-based IVI platform includes a high-speed synchronous serial port to allow streaming of low-latency audio and voice from a Bluetooth chipset. The platform also offers a complete Bluetooth software stack and Bluetooth profiles for audio streaming and hands-free calling. WiFi controllers can be attached to the platform through PCI Express, USB, or SDIO.

Power Management

The Intel-based IVI platform has its own local power management architecture to manage the SoC and the automotive I/O fabric, with the associated policies. In addition, an automotive power state manager (PSM) can exist as a central entity to keep track of the overall power states in an automobile and respond to events like Ignition On/Off, Drive-Idle, Under/Over Voltage Events, Manageability Service calls, and so on. It is beyond the scope of this article to describe the PSM.

Traditional Intel architecture platforms support various power management capabilities, to conserve power and this applies to both battery and AC powered platforms. The Intel-based IVI platform system does support the power management states as shown in Table 4.

Table 4: Intel-based IVI platform power state usage

As it was highlighted earlier, one of the key design goals of the Intel-based IVI platform is a fast boot in the order of seconds. Typically, any resumption from Suspend/Hibernate back to active state involves restoring the previous state. In an automobile environment with multiple users of the same vehicle, it is challenging to resume from suspend, as the users might change across these transitions and one users context could get inadvertently restored for another user. This makes the fast boot with a completely fresh state on every power on a key requirement for the platform, so that every user always starts with a new context. In addition, long duration S3 states may drain battery power if not handled properly.

The built-in clock throttling feature of the Intel-based IVI platform can be used for thermal management, in addition to power managing the idle I/O devices. However, the actual usage model is left to the OEM and can be used in conjunction with the climate control system of the automobile.

Conclusions

Enabling the standards-based the Intel-based IVI platform on Intel architecture is opening up many opportunities both from a technical innovation and business opportunity standpoint. The scope of these opportunities will further expand with the wide availability of WiMax/4G infrastructure for the connected car usage model. In consideration of the combined technical and market requirements in automotive infotainment, leading automobile manufacturers and suppliers announced in March 2009 the formation of the GENIVI Alliance, a nonprofit organization committed to driving the development and broad adoption of an open source In-Vehicle Infotainment (IVI) reference platform.

By removing the costly duplication in specifications and lower level software functions, opportunities for new services desired by automotive customers can be developed instead, resulting in new sources of revenue. Based primarily on key technical working groups, the outcome of vetted specifications and reference implementations will be available to all members for commercial development along with many elements planned for release into open source.

The new Alliance (expected to reach up to 150 companies by 2010) will unite industry leading automotive, consumer electronics, communications, application development and entertainment companies investing in the IVI market to align requirements, deliver reference implementations, offer certification programs and foster a vibrant IVI community with the purpose of removing waste from the development cycle.

For More Information

Microsoft Auto Platform Overview

Moblin for IVI: Software Architecture Overview

Intel Atom Processor Z5xx Series and Intel System Controller Hub US15W Development Kit

Intel Active Management Technology (Intel AMT)

Media Oriented System Transport Technology

Acknowledgements

The authors would like to acknowledge the following for their feedback and contributions to the paper: Staci Palmer, Peter Barry, Lomesh Agarwal, Matt Sottek, Lindsey Sech, Steve Adams, Scott Hoke, Lynn Comp, Sam Lamagna, and Mark Brown.


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