Autonomous Vehicle Engineering - July 2021 - 16

V2X
An additional step to eliminate the interference is to
look at the radar sensors in traffic as multiple units of
the same sensing system. In this vision, the radar sensors
work together to achieve the same shared goal.
channel, similar to the CSMA-CA protocol used in
Wi-Fi networks. Further exploration is required to
identify the proper resource allocation protocol for
radar applications. It should be based on the MAC
protocols but with significant adaptations to consider
the different kinds of traffic, priority settings, and
quality of service targets.
Whatever the solution will be, an agreed way to
access the shared resources will surely increase the
maximum number of radar sensors co-existing in the
same environment.
Cooperative sensing
An additional step can further be taken to eliminate
the interference. Instead of looking at the radar sensors
as individual units, one could look at the radar sensors
as multiple units of the same sensing system. In this
vision, the radar sensors work together to achieve the
same shared goal. They will need to be equipped with a
communication link to all other sensors to coordinate
access to the shared channel and share information,
acting as a larger ecosystem.
An example of how this would work in a scenario
would be when an application needs to have a good
16 July 2021
image of the environment. It could query the radar
sensing system to build that image; however, the information
might come from a radar sensor mounted on a
different car or road infrastructure. Such cooperative
sensing would avoid the interference a priori because no
unit is seen as an interferer, but they all work together.
The proper radar interference mitigation strategy
does not need to be the most efficient. Having the right
balance between complexity and capability of dealing with
the interferers strongly depends on the foreseen scenarios.
Combinations of randomization, detection and avoidance
of interference might be powerful enough to support a
significant market penetration of radar sensor systems.
There will be more elaborate techniques to deal with
radar-to-radar interference. Eventually, there will be some
form of agreement within the radar sensor community to
share the sensing resources effectively. Ultimately, there
will be a standardized way to access the communications
channel while, at the same time, maintain the possibility
to have differentiating sensing performance. ■
For further information, see:
https://www.nxp.com/applications/automotive/
adas-and-highly-automated-driving/automotiveradar-systems:RADAR-SYSTEMS
AUTONOMOUS
VEHICLE ENGINEERING
NXP

https://www.nxp.com/applications/automotive/adas-and-highly-automated-driving/automotive-radar-systems:RADAR-SYSTEMS

Autonomous Vehicle Engineering - July 2021

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