Subject: [6gip] 6G and V2X

From: Alexandre Petrescu <[email-masked]>
Date: Wed, 13 Jan 2021 10:47:33 +0100

Hi,

I would like to discuss about V2X in 6G.

There is currently lots of works about V2X in general, such as the
ETSI's CAM messages in Europe and the BSM messages in US (Cooperative
Awareness and Basic Safety Messages).  If I remember correctly, some V2X
messages such as the CAMs are specified in 3GPP documents as well.  In
trial deployments these CAM messages were sent on UDP on IP and on 3G
and on 4G; presumably it will be easy to be put on 5G as well.  The most
recent 5G demo for self-driving automobiles was in Sweden at the
beginning of October of year 2020; it is not clear whether that used V2X
messages, or just 5G.

Are CAM messages link-layer messages in 5G-V2X?

In my oppinion, in the future, there will be no specific 5G-V2X
deployment, no more than 2G, 3G or 4G had anything specific about V2X.
There might be something like specific 5G slices for automobiles, but no
V2X messaging.  It means that the V2X messages will not be at the link
layer in 5G.  This is a speculation of my part, but that is what I think
at this time.  I might be wrong.

This brings me to the reason of why mentioning V2X.

It might be appropriate to specify how are the V2X messages used on 3G
and 4G.  This is to put CAM on UDP on IP.  Maybe BSM would be done the
same.  Maybe then 3GPP could put both CAM Mand BSM in 3GPP specs, not
only CAM as it stands now (IIRC).  This is a great opportunity for
specification that is in relationship with deployments.  Whether 3GPP
accepts to put BSM in 3GPP specs might be a matter of time.  Is it too
late?  Then do it on 6G.  Is BSM already in 3GPP specs?  Then we have a
problem of interop between e.g. an 5G-enabled US car and a server in Europe.

I would like to say that V2X is not all there is to be about automobiles
and 5G.  There are also a number of automobile-related use-cases that
need some specific features from 5G.  E.g. tele-operated driving is one
such use-case, and we could work on others.  These use-cases require the
bandwidth/latency of 5G but that might not be enough.  New use-cases
related to automobiles might take more advantage of higher bandwidths
and even lower latencies at 6G.

Finally, allow me to make a speculation about spectrum use on cellular
networks.  A year ago there was a public consultation of FCC considering
to take spectrum from the 5.9Ghz space that is typically allocated to
non-cellular technologies like DSRC.  It seems to me that consultation
has not reached a decision.  I do not know.  It might be that there will
be no spectrum at 5.9GHz for cellular technologies and that 5.9GHz will
stay for WiFi-like technos (802.11-OCB, .11bd, etc).  If things at
5.9Ghz stay the way they are now, then this would be even more support
for considering that V2X in 5G will not be anything like CAM as a 5G
link layer message, so again, V2X will be more like UDP on IP.  It might
be that 5G does not accept that.

Alex