Autonomous Vehicle Engineering - January 2022 - 19

Emerging Technologies
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Network architects need to understand how the vehicle will be required to
scale as the technology improves - and more ADAS/AV capability is added.
connectors, along with mating connectors at either end.
Ultimately the wire harness is responsible for moving
control and payload data, as well as for providing DC
power to remote sensors. Channel characterization
for SerDes link consists of both time domain and
frequency domain analysis. This requires looking at
the cabling system, the MDI, and the fixturing and
test setup requirements.
The actual MDI connector is not standard, but
there are some rigid specifications to help ensure that
interactions between the MDI and cable are minimized.
Figure 4 provides an example of an H-MTD
connector that is being used for multi-gig automotive
Ethernet and could also be used for emerging SerDes
standards. When we look at the channel tests, we
are looking for errors such as impedance mismatch;
signal distortions or defects, and cross talk between
the cables.
Receiver testing
Receivers are responsible for making sense of the data
sent over the link, then passing it along for further
processing in an ECU or display device. Bit errors at
the receiver result in lost or corrupted data coming
from safety-critical sensors like camera, radar and lidar.
Proper receiver functionality becomes increasingly
difficult for complex modulations like PAM-4,
especially when sent over long channels exposed to
many simultaneous sources of noise. To characterize
the receiver's capabilities, one must measure error levels
in the presence of multiple noise sources, including
narrow band interference; bulk current injection; transients
on-line and alien cable bundle crosstalk.
The measurement setup can include noise sources,
amplifiers and coupling circuitry that allow precise
levels of noise to be injected onto an active SerDes link.
The DUT's signal quality registers are then queried to
verify whether the receiver could interpret symbols
correctly in the presence of noise. The emphasis in
receiver testing is to stress the receiver to ensure it can
still maintain BER rates.
The future of mobility involves more cameras, more
connections and more sensors with greater accuracy,
less weight and increased safety. Undoubtedly, there
will be a need for an in-vehicle network to seamlessly
handle these challenges. Those in-vehicle networks will
need to be tested, they will need to be interoperable,
and they will need to be secure. ■
Carrie Browen is the autonomous vehicle business line product
manager for Keysight Technologies. Kevin Kershner is responsible
for defining the requirements for Keysight's future IVN
solutions and is an active participant in MIPI A-PHY, ASA and
VESA standards meetings.
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Autonomous Vehicle Engineering - January 2022

Table of Contents for the Digital Edition of Autonomous Vehicle Engineering - January 2022
