Wireless technologies accelerate the next wave of in-vehicle innovation
Bluetooth, Wi-Fi, and Near Field Communication are shaping today’s in-vehicle infotainment designs and promising to provide the next generation of vehicle-to-vehicle communications such as traffic management, incident avoidance, and social networking. By implementing a single chip that combines all of these radio technologies, designers can help solve many of the complex design challenges facing systems engineers using multiple wireless communication protocols in their designs.
From climate control touch-screen dashboards to smartphones that read text messages aloud in the car, the buzz surrounding In-Vehicle Infotainment (IVI) systems has reached a fever pitch. As car manufacturers scramble to build advanced infotainment systems that bring all elements of the entertainment experience on the road, they require new, advanced wireless technologies. But which specific wireless technologies do manufacturers need to transform cars into sophisticated mobile entertainment systems?
Technologies enable true IVI experiences
Although major automotive manufacturers have already begun introducing various IVI technologies, enabling true in-vehicle wireless entertainment requires standards-based technologies built on a single System-on-Chip (SoC). The next wave of IVI applications will rely heavily on three wireless technologies – Bluetooth, Wi-Fi, and Near Field Communication (NFC) – built on one combination radio chip. And as the market continues to evolve, OEMs will need to leverage traditional Wi-Fi rolling hot spots to offer vehicle-to-vehicle communications such as traffic management, incident avoidance, and social networking.
Some use cases for in-vehicle Bluetooth technology are relatively well-known and others will become more apparent as the popularity of in-vehicle wireless infotainment grows.
The most popular application for Bluetooth technology today is hands-free driving. In many states, Bluetooth not only solves safety issues associated with using mobile technology while in the car, it also fulfills government mandates calling for hands-free driving. Another popular use case for the technology is audio streaming. By leveraging Bluetooth, consumers can stream songs from their smartphones and play music on their speakers, allowing them to transform their smartphone into a car stereo.
The Bluetooth SIG has specified a standard mechanism for streaming high-quality mono or stereo audio from a Bluetooth master such as a smartphone to a slave device like an IVI system. The Advanced Audio Distribution Profile (A2DP) encodes 2-channel audio in a Bluetooth-friendly format, which is sent wirelessly and decoded at the Bluetooth receiver. The SBC audio codec is a mandatory component of the A2DP profile, but other industry standards and proprietary codecs can also be accommodated.
Today, several proprietary radios enable keyless entry and proximity sensor capabilities to unlock car doors or start the ignition. But because these links are not based on standards, each accessory must be compatible with the specific proprietary technology or it will not work.
Wireless SoCs that include Bluetooth Low Energy (LE) capabilities, however, enable interoperability with all in-vehicle wireless systems, allowing consumers to use any of their mobile accessories to open car doors or start the ignition.
The advent of the Bluetooth LE specification represents a paradigm shift in efficiency, enabling dramatically increased battery life for Bluetooth products. The LE specification enables use cases and products that consume very little power, allowing the development of small sensor-based products that can survive on a small cell (such as a watch) battery for several years. This innovation will help drive Bluetooth technology into keyless entry fobs and other new applications that previously were out of reach from an efficiency standpoint.
Given the broad proliferation of Bluetooth in mobile products, a wide variety of devices can be used in automotive applications to remotely control a vehicle for security, climate control, ignition control, and other functions. Bluetooth LE profiles are used to define a specific behavior when two Bluetooth LE-enabled devices come close or move farther away from one another. By monitoring the absolute RF path loss between the two devices, the relative distance between objects can be ascertained. Furthermore, actions such as locking or unlocking the doors, starting the ignition, and choosing preferences such as climate, seating adjustments, multimedia selections, and other user-specific profiles can be set when the driver approaches or leaves the vehicle.
Standards-based HD Video over Wi-Fi
Today, consumers rely more on their mobile devices than ever before. In turn, this reliance has created heightened demands for technology that allows consumers to access and display all of their personalized smartphone data directly in their car. To ensure this seamless transfer of information between the mobile and automotive ecosystems, car manufacturers must leverage standards-based technology that enables consumers to carry any phone into any car and transfer data wirelessly.
An upcoming industry-standard specification that defines an interoperable mechanism for reliable, point-to-point HD video transmission between two Wi-Fi-enabled devices is expected from the Wi-Fi Alliance in the second half of 2012. Although video over Wi-Fi applications have been available for quite some time, this is the industry’s first attempt to develop an interoperability specification for video distribution. It specifies provisioning and management for negotiating video capabilities between a source and sync device, standard video transcoding schemes built on H.264, transport and control schemes, packetization, and content protection based on High-bandwidth Digital Content Protection (HDCP) 2.0. Many of the device and service discovery components of the protocol are built around the previously released Wi-Fi Direct specification.
The WI-FI CERTIFIED Miracast specification enables car manufacturers to wirelessly mirror smartphone screens to in-dash LCDs, creating an immediately personalized interface in the dashboard. Additionally, this standards-based technology allows consumers to safely control smartphones through the dashboard so they can answer calls and check text messages.
WI-FI CERTIFIED Miracast can support a variety of frame rates and video resolutions depending on the capabilities of the source and sync device. The specification will support up to full 1080p HD video at 60 frames per second, with extensions for 3D video. Provisions are available for low-latency transmission to enable display mirroring and real-time gaming over the link. A user interface back channel is available to allow remote control of video (play, pause, rewind, and so on) and other functions such as mouse and keyboard.
Although NFC is often associated with cashless payments, its ability to deliver security features to IVI systems is instrumental in providing an optimal end-user experience.
NFC operates in the unlicensed 13.56 MHz band and can be used as an out-of-band communication link for Wi-Fi and Bluetooth. Setting up a link via Wi-Fi or Bluetooth is a complicated process that the average consumer is unable to accomplish, but by implementing NFC, consumers can simply touch their phone to the NFC receiver in a car and secure a wireless connection, rather than having to search for networks or set up a W2A pass phrase.
One primary advantage of using NFC to provision a Bluetooth or Wi-Fi connection is that NFC is easier to set up than more complex radios, and the setup time is generally shorter (on the order of milliseconds). NFC leverages the principle of magnetic induction to establish a communication link between two devices employing loop antennas. The effective range of link is no more than a few centimeters, so the user experience for setting up the connection is built around close proximity or touch.
Moving beyond in-vehicle communications
While automotive manufacturers must focus on Bluetooth, WI-FI CERTIFIED Miracast, and NFC to optimize in-vehicle wireless infotainment, the next wave of innovation will be outside the car.
To suit the needs of the 2012 consumer, automotive manufacturers have begun leveraging Wi-Fi rolling hot spots to enable streaming music and videos in vehicles. Several upcoming use cases will drive even further adoption:
- Vehicle-to-home: This will allow a vehicle to automatically sync with a home media server so consumers can download music, videos, and more multimedia content.
- Vehicle-to-Internet: This will allow a vehicle to sync content with various public hot spots. For example, a car can remotely deliver diagnostic information to a manufacturer or dealer to keep it adequately serviced and running longer.
- Vehicle-to-vehicle: This technology will provide incident-avoidance features and allow various social networking functions including location-based services, offering capabilities such as alerting a consumer when they have a friend around the corner.
Multiple connectivity features on one chip
To integrate next-generation in-vehicle wireless technologies, the car of the future must leverage combination radios. Therefore, it is essential to implement a single wireless chip that can enable all of these connectivity functions in the vehicle.
By building multiple complementary radio technologies into a single piece of silicon, designers can solve some of the most difficult design challenges facing systems engineers using multiple wireless communications protocols in their products. One example of such a product is Marvell’s Avastar 88W8787 (Figure 1), an IEEE 802.11a/b/g/n 1x1 + Bluetooth 3.0 + FM wireless SoC that is widely adopted in smartphones, tablets, mobile routers, portable gaming, cameras, and other consumer electronic products. The device is also qualified to meet the stringent quality and reliability requirements for automotive applications, and is thus well-suited for today’s IVI systems.
IVI systems in particular offer multiple use cases for concurrent radio operation, and great care must be taken to preserve the user experience in those situations. Technologies such as Long Term Evolution (LTE), Wi-Fi, and Bluetooth operate in the same or adjacent frequency bands, and special techniques must be employed to enable concurrent operation while minimizing the impact of interference among the radios. Antenna-sharing techniques and complex Time-Division Multiplexing (TDM) algorithms are effective strategies for assigning priority and arbitrating airtime between the radios to ensure a robust user experience. The implementation of these techniques is dramatically simplified when all the technologies come from the same vendor and reside on the same chip.