Subject: [ipwave] example of problematic PHY setup

From: Alexandre Petrescu <[email-masked]>
Date: Fri, 12 Apr 2019 15:30:43 +0200

In my explanations I often say that PHY and MAC must be setup properly 
in order for IP to work on them.  It's good to use the right channels, 
to understand the propagation models, etc.

Here is one example of problematic PHY deployment from the world of 
lidars (it's a PHY, but it's not message exchange nature; it's more 
bouncing signal nature).

This recent deployment of lidar on pole is probably targetting sharing 
its data with cars on 5G.  The lidar is apparently a Quanergy M8 model.  
I strongly suppose it does not see right under it.  It may work on a 
distance, but not immediately below it.  It is a problem.

It is the same kind of problematic issues that are also done with many 
OCB IP-RSU deployments: their PHY covers in places they should not (e.g. 
outside the road) and their coverage on the road is lesser.

These kinds of problems of PHY deployment lead to wrong things happening 
at PHY, at MAC and implicitely at IP layer.

But it is not because of IP, nor because of ND.

One cant fix these problems by improving ND.  Maybe a little ND timer 
tweaking could help something, but much less than what an angled lidar, 
or focused MIMO OCB antennas could solve.

Alex