Audi A8 LTE.automotiveIT

Audi is testing the new LTE mobile communication standard with a long-wheelbase A8 model (Photo: Audi)

Carmakers are increasing their efforts to improve car connectivity through the introduction of LTE.

The new standard, which is set to increase the speed and capacity of mobile communications, is still in the trial phase in most countries. But experts expect the new mobile communication network to be fully operational in major markets within two years.

That leaves little time for car companies to prepare for LTE, which explains why a premium brand such as Volkswagen Group's Audi already has LTE-equipped test models on German roads.

The new mobile standard will allow video streaming, music downloads, conference calls and a broad range of new car-to-car and car-to-infrastructure communication features. Such functions are currently limited by the capacity constraints of GSM networks.

AutomotiveIT test drove one of Audi's LTE-equipped A8 models and found that even early versions of the technology provide much faster connectivity than what is available now.

In tests near Cologne and Ingolstadt, Audi registered download speeds of 45 Mbps, which is lower than stationary LTE speeds of 100 Mbps, but significantly faster than what can be achieved with current networks.

As carmakers prepare to jump on the LTE bandwagon, they still have to sort out a range of issues. One of these is the familiar problem that available bandwidth declines as the number of users of a particular cell increases.

Another issue is that data transfer rates decline near the edge of a cell.

And third, there is the issue of "latency" or the standard delay built into all mobile transmissions. In mobile LTE tests carried out by Audi, that delay was 37 milliseconds. That's no problem for in-car entertainment, but it's much too long for car-to-car and car-to-infrastructure communications. Because latency affects safety, automotive developers want a delay of less than 5 milliseconds.

Short latency isn't the only requirement the auto industry has. Audi also wants LTE connectivity to be fully functional at top speeds of up to 400 km/hour.

Despite these challenges, car companies are optimistic that LTE will allow a quantum leap in car connectivity. The standard will replace GSM, which, despite its maturity, suffers from uneven coverage and severe capacity problems in the face of ever-increasing data flows.

-By Hilmar Dunker