Nuts and Volts - February 2018

10 February 2018

status, and other similar information. Nearby vehicles get the message and send out their own. All the cars within a given area know where everyone is located and what they are doing.

Intelligent software will determine potential conflicts and generate warnings to the drivers. Some vehicles may tie the DSRC outputs to the ADAS that may further activate automatic braking or engage steering control.

Cellular V2X

DSRC has been around for years, and it has been tested and approved by the NHTSA. Chips and modules are for sale because it’s all ready to go. However, only one model of Cadillac has one installed. The rollout has been stalled because a competitive technology has been put forth by several companies.

Called cellular-V2X or just C-V2X, the technology is based on the current cellular radio standard Long Term Evolution (LTE). The C-V2X version of LTE permits direct V2V, a broadcast mode, as well as connections to the existing cellular networks to access networks that may be relevant.

As for specs, C-V2X operates in the same 5. 9 GHz spectrum and has a similar range and data rate. One touted feature is a lower latency (delay or response) time than DSRC. It too will transmit and receive the BSMs and generate warnings and vehicle action.

C-V2X has not been as widely tested as DSRC. Nevertheless, it’s a proven wireless standard that should be more than competitive.

What Technology Wins?

It’s difficult to predict which standard will win the automotive marketplace. Both will serve the purpose well. C-V2X has the advantage of being able to use the existing cellular network infrastructure for V2I and V2X It’s not clear at this time what standard the auto manufacturers will adopt.

ADAS and Self-Driving Cars

Fully automated vehicles (AVs) — commonly referred to as driverless vehicles — actually do drive themselves. There are various stages of autonomy as shown in the accompanying Table 1. In the simplest form, AVs are basically an extension of ADAS that are common on many vehicles.

ADAS include things like: y Back-up camera. A dashboard screen really aids when going in reverse. y Lane departure warning. Cameras follow the white and yellow stripes, and signal when you stray. y Blind spot detection. Detects objects and vehicles on either side. y Adaptive cruise control. Speed is automatically adjusted to the prevailing traffic. y Automatic braking. Activates brakes when objects are detected; front or back. Additional ADAS features include: y Tire pressure monitoring. y Adaptive lighting. Automatic high beam control and rotating headlights for curves. y Driver monitoring. Detects drowsiness or inattention, All of these features are designed for safety. They help the driver with warnings, or may actually take control from the driver when the driver fails to react to a potential crash situation.