Wireless cars must make test connection, says Keysight

Connected cars with wireless communications links, telematics and vehicle advanced driver assistance systems (ADAS) will require increasing levels of electronic test, write John Russell, Bill Mckinley and Matt Hodgetts

The technological sophistication of modern automobiles means that they are very different from the models of the past.

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Figure 1 gives an idea of how the percentage that the electronics content contributes to the total cost of a car has been steadily rising, and is expected to keep rising.

In many areas conventional mechanical systems have been replaced by sophisticated electronics. This is allowing substantial improvements in their operational efficiency, as well as enabling a wider range of new features and functionality to be benefited from.

In many ways the cars that are being introduced onto the market today have much more in common with computing devices than they do with their predecessors. They will, in some cases, need to process in excess of 25Gbyte of data per hour in order to fulfil all their assigned tasks.

Until now the impetus for implementing digital technology into automotive designs has been mainly for the purpose of eliminating mechanical elements. Through this, marked reductions in vehicle weight are now happening, which in turn improves fuel economy figures.

This is just one aspect. Vehicle manufacturers are moving ever closer to their goal of the ‘connected car’. Such vehicles will integrate systems supporting a broad array of different communication technologies – and through these it will be possible to address issues relating to driver/passenger comfort and safety, as well as vehicle security.

It will also make it easier to ensure the vehicle is kept in good working order and that maintenance/repair requirements are identified in a timely manner.

Industry analysts firm Gartner has forecast that by 2020 there will be over 250 million connected cars on our roads. These vehicles will employ various different wireless protocols. These include Wi-Fi, LTE mobile, Bluetooth, NFC and ZigBee, to name just a few.

This presents vehicle manufacturers and their technology partners with a sizeable and multifaceted challenge. Not only do they need to derive an accurate benchmark of each of these protocols in isolation, on top of this they must gain a firm grasp of how the wireless signals will interact with one another and also what influence the extremely difficult automotive environment in which they are located is likely to have on performance.

There are several different parts of a vehicle’s operation where the heightened degree of connectivity now envisaged is destined to have real value. These include: infotainment and communications; telematics; and vehicle advanced driver assistance system (ADAS).

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Figure 2 gives further details about some of the different applications that are encompassed in each of these three areas

Car makers want to provide all these extra capabilities, but given the highly competitive market they need to be able to do this in a way that doesn’t bring excessive additional costs with it. It is crucial, therefore, that testing activities do not slow down the production process or require allocation of extra engineering resources.

Main test requirements

Though in the telecoms sector, data rates are the overriding concern, for connected cars it will be low latency and elevated reliability that matter.

Through the test equipment they have sourced, engineers need to be able to not only verify performance of the automotive wireless technologies being utilised, but in addition carry out comprehensive interference and interoperability tests. So, in addition to rapid throughput, a breadth of test parameters is basically mandatory.

Scalability is also of great importance. Testing within a laboratory scenario is just the beginning. The product lifecycle as a whole has to be adequately attended to, not just isolated elements. Once the necessary tests have been accomplished during the development phases, these activities need to be ramped up to meet mass production demands. It is important that the specified equipment is able to deal with this migration.

The role of 802.11p in connected cars

802.11p is set to form the foundation on which much of the functionality in connected cars will be constructed. This is an approved amendment to the universally recognized 802.11 WLAN standard. It deals with wireless access inside an automotive setting and will support Intelligent Transportation System (ITS) applications as they start to emerge.

Occupying the 5.9GHz frequency band, 802.11p utilises a series of 10MHz wide channels (six service channels, plus an addition channel for control purposes). The priority with this protocol is not offering a high data capacity, it is about establishing a highly reliable, low latency wireless data link.

This more deterministic technology will make it possible for vehicle-to-vehicle or infrastructure (V2V/V2I) communication to be implemented. A vehicle will be able to broadcast data relating to its current position and the speed/direction in which it is travelling. This data may then be picked up and, if necessary, acted upon by other vehicles that are in the vicinity.

John Russell and Bill Mckinley work for Keysight Technologies and Matt Hodgetts is with Microlease.


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