Under V2V, combining a dedicated frequency spectrum (the 5.9 GHz band for the US and Europe and the 5.8 GHz band for Japan) and ad-hoc network architecture enables a “heartbeat” message, broadcast by each car 10 times per second, Juliussen explained. “It is a relatively simple and cost effective solution” for avoiding collisions, for example, easily incorporated into mass market cars.
The downside of a safety system based on V2V, however, is that such safety features work best when every car on the road is equipped with DSRC-based features. In other words, V2V needs a universal mandate, explained Juliussen.
Beyond safety features, another benefit of a V2X infrastructure, said Juliussen, is “improved efficiency in traffic.” When cars need to pass through a number of traffic lights, the V2X infrastructure can inform drivers of a recommended driving speed, in order to reduce unnecessary acceleration or slowdown.
NXP’s Freeman agreed. Noting that safety and environmental impact are the real impetus behind V2X, he pointed out that efficient traffic flow allows individual cars to waste less fuel. Even though Freeman believes the combination of the current ADAS and LTE “can go a long way” to address the safety issues, “V2X really add[s] tremendous value to society,” he claimed. “Benefits are fantastic.”
While acknowledging that LTE can also add value to the future of V2X infrastructure, Freeman sees all the possible components as complementary. The DSRC-based V2V and V2I can offer necessary safety messages “without tying up people’s mobile bandwidth,” he added.
With its 802.11p chips designed to work in the DSRC spectrum, NXP today is participating in roughly half of the current road trials (based on the DSRC spectrum) worldwide. “As a chip company, you don’t necessarily want to be too early to the market, but we hope to help create the market [for V2V],” said Freeman, “by offering the underlying semiconductor architecture.”