Flexible and Scalable Platform
The traditional automotive design approach has been to develop very specific, tailored, and inflexible solutions based on the OEMs or auto manufacturers defined needs. Telematics and infotainment is forcing the industry rethink about the products and systems architected into a typical "connected car." The convergence of the consumer world into the vehicle, in applications such has telematics, has forced "consumer development" thinking into an industry that is traditionally slow, conservative, and cost driven.

New requirements carried across from the consumer industry demand rapid change, as consumers always expect to have the next "big thing." This is forcing the need for flexible architectures that can cope with not only current applications but future and possible unknown features. This conflicts with the multi-year development cycles that typical automotive electronic designs generally need. It is now essential that a platform designed for the future has enough anticipated system resources and bandwidth to cope with changes throughout the development cycle.

As with any platform, flexibility and scalability are key to successful adoption of the architecture, from basic systems through to high-performance, high-end telematics systems. With this in mind, Microsoft has developed a true automotive standard telematics platform that is highly customizable and scalable to suit the end customer's needs. The platform incorporates an ARM 9 based Microcontroller, supports memory from 32MB Flash/32MB DRAM upwards, embedded GPS, Bluetooth, GSM phone module, CAN controller, as well as protected analog and digital I/O such as LED drivers and button inputs.

Microsoft took advantage of the flexibility and high integration possibilities of Field Programmable Gate Array (FPGA) technology. The FPGA was used within this platform for multiple independent purposes such as a GSM phone interface, vehicle interfaces (CAN controller and K-line), and sophisticated audio functions and paths as shown below. The high levels of integration that FPGAs offer to this type of architecture also have the advantage of containing multiple buses, interfaces, and clocks within one device—making the design EMI (electromagnetic interference) more manageable for the product designer. It also has the obvious advantage of reducing component count and therefore board space. All of these lead to lower production costs and higher quality of manufacture—important factors in any automotive design.

Understanding the nature of vehicle development and the multitude of vehicle interfaces available, Microsoft intentionally architected a flexible solution, which allows rapid changes to the back-end vehicle interface without affecting the underlying architecture and performance of the system. For example, in the future it would be possible to scale the FPGA to suit the needs of the end application with automotive buses such as MOST, FlexRay, D2B, or IEEE-1394 to name a few.

Central to the platform is the voice recognition (VR) system. The audio path within any system with VR is an external microphone, analog input (biasing and filtering), digitization, and digital filtering before it is finally presented to the VR engine for speech processing. Within this path there are multiple opportunities for unwanted noise to be introduced into the system—both onboard the electrical platform and within the vehicle environment, even prior to the electronics. It is the job of the both the product developer and the system integrator to ensure that microphone position and type is correctly suited to the application and environment.

In a perfect world the VR engine will receive clean, consistent speech signals—this is never the case in the automotive world. Given the dynamic nature of the vehicle environment, acceptable voice recognition implementation is not a straightforward exercise. Factors such as vehicle speed, window position (open/closed), road noise, and weather conditions (rain/wind) are added to the already difficult VR problems of languages, accents and gender.

These new dynamic factors specific to the automotive environment have increased the importance of signal preconditioning prior to the VR engine. This environment has created the need for highly adaptive digital filtering algorithms. Microsoft made the choice to implement this signal conditioning in hardware by using the FPGA's DSP parallel processing capability. Of course, this pre-processing could be possible in application specific standard products (ASSPs) such as dedicated DSP chips, however the advantages gained through the high levels of integration of other parts of the platform would be lost.

In general the combination of telematics and voice recognition allows implementations of adaptable and upgradeable VR engines and DSP filters tailored to suit certain types of users and environments—for example: Language: English; accent: Scottish; gender: female.

The importance of designing automotive products, especially in the infotainment section of the vehicle, with sufficient spare bandwidth to cope with new and unexpected future upgrades also applies to the FPGA. It is now becoming clear to automotive OEMs that intelligently architected flexible software and hardware solutions are a necessity in future platforms.

Down the Road Today's motorists are talking on the phone, enjoying their personal music selections and looking for directions—all while driving. The joint telematics solution gives easy access to all these applications. Diagnostic data can be transferred to and analyzed by the manufacturer and the dealer.

Later this year, Fiat customers will be able to purchase vehicles with new systems offering several levels of connectivity. Key features among these systems include seamless integration of customers' own devices such as cellular phones, Pocket PCs, or Windows Mobile devices using Bluetooth connectivity for access to contacts, appointments, and making hands-free calls. In addition to hands-free phones, motorists can access Web services for off-board navigation and real-time traffic.

Drivers and passengers will also enjoy digital music in the car through a USB port on the dashboard for easy connectivity to personal electronic devices. All systems will feature high-quality speech recognition. As a result, Fiat customers will more easily be able to make calls, access contacts, and other information stored on their own PDA or mobile phone over the car audio system hands free—all by simply using their voice.

David Vornholt is strategic relationships manager for Xilinx, Inc.