Dedicated Short Range Communications

 

Dedicated Short Range Communications (DSRC) combines high reliability wireless connectivity, accurate positioning (via global positioning satellites and vehicle dead-reckoning) and an on-board computer to allow vehicles to communicate directly to each other (vehicle-to-vehicle, or V2V links), and to road-side units (vehicle-to-infrastructure or V2I).


DSRC provides a very robust, low-latency radio connection, even in safety-critical, non-line-of-sight conditions. This gives cars the ability to “see around corners” and to “see through other vehicles”. Similarly, it enables infrastructure to know about the detailed traffic movements and to communicate with vehicles.

In the future, systems could even take automatic intervention, via interface to the vehicle control system (using the standard controller area network, or CAN bus), e.g. to automatically increase brake pressure, arm airbags and pre-tension seat belts in the case of an unavoidable crash.

 

In addition to these important road safety applications, DSRC provides an open, standardised platform for active traffic flow management, road and traffic condition monitoring, traffic scheduling, and optimised route selection.  The emergence of the connected vehicle also provides a new platform for many other applications.


DSRC has the full backing of the global automotive industry, and is based on published standards developed by international organisations such as the Institution of Electrical and Electronic Engineers (IEEE) and the Society of Automotive Engineers (SAE). The wireless communications standard is IEEE 802.11p, a relative of WiFi. These standards ensure that vehicles and equipment from different manufacturers can interoperate.


The word “Dedicated” means that DSRC operates in its own protected frequency band at 5.9 GHz. This ensures that the system does not suffer from interference from other wireless technologies. This band has already been allocated in the United States and Europe. ConnectSafe has obtained the first scientific license for operation in the 5.9GHz band in Australia.

DSRC-equipped vehicles broadcast basic safety messages ten times a second. These messages contain detailed dynamic information including latitude, longitude, speed, heading, four-way acceleration, brake status, steering wheel angle, throttle position, and vehicle size.


Allowing vehicles to communicate with each other, and the broader environment, provides the vehicle with greater knowledge of its surroundings, and hence the ability to avert hazardous situations such as potential intersection crashes, rear-end collisions, dangerous overtaking, lane drift or imminent road departure. On board units can alert drivers to hazardous situations via audio, visual or haptic human-machine interfaces.