Trends affecting automotive RF system tests

These days, a car is far more than a means to transport quickly and safely from A to B: it is a comprehensive living space in which we can be informed, entertained and productive just as effectively as when at home or in an office. All these electronic features have their specific needs and requirements for testing.

Many varieties of wireless communication technology have made this evolution of the car possible. They include GPS for satellite navigation, cellular (mobile telephone) technologies for communication and access to the internet, Wi-Fi for internet access and car-to-car (C2C) communication, DSRC (Dedicated Short-Range Communication) for automatic payment of tolls and parking fees, Bluetooth for hands-free communication, and several others.

The evolution of the car is far from ended, however, and so now RF engineers in the automotive sector are facing new development challenges which are going to change the scope, duration and complexity of the RF testing carried out on components, modules and complete vehicles.

This article highlights three big trends that automotive engineers in charge of RF testing will need to take account of in the years to come. From both a personal and a corporate point of view, it will be beneficial to address these emerging requirements early: They are:
 • The increasing application of rigorous functional safety concepts to RF systems
 • The requirement to test highly dynamic wireless networks in which connections and routing are changing second-by-second
 • The operation of the car as a piece of mobile telephone user equipment, just like a handset and as a bridge application for e.g. eCall application.

Testing RF systems for functional safety
Today, the wireless interfaces in a car, and their applications, are important and need to function well if they are to give the car's users a good experience. But none today is actually safety-critical: the driver has full control of the car's motion.

This is starting to change, as car manufacturers introduce increasingly sophisticated driver-assistance systems. Eventually, it seems inevitable that fully autonomous self-driving vehicles will become a reality.

In the development of autonomous vehicles, car manufacturers will clearly implement exhaustive testing regimes. These will comprise public road testing, virtual testing, fail-safe testing, simulations, traffic scenario testing, safety and crash testing, cyber-threat testing and other categories of tests. Governments and citizens will want to be sure that these vehicles meet exacting regulatory, legal and technical requirements.

And while this has an impact most obviously at the level of the complete vehicle, RF systems will also come under closer scrutiny, since they will become safety-critical when used in autonomous vehicles.

So what is meant by a self-driving car? A fully autonomous vehicle can drive to a specific location in real traffic without the intervention of a human driver. Advanced Driver Assistance Systems (ADAS) are systems which either help the driver to drive safely – for instance by alerting the driver when dangerously close to the vehicle in front – or which actually enable the self- driving process.

Radios used in autonomous cars will include radars for measuring the distance to the vehicle in front, and that vehicle's speed and direction of travel; and – as will be described below – car-to-car communications for sharing information about road and traffic conditions. In an autonomous vehicle, these radios are safety-critical. For this reason, testing radios according to their technical specification, as automotive suppliers do today, will no longer be adequate. There will also need to be processes which support compliance with the requirements of the ISO 26262 functional safety standard.