Re: [ipwave] FCC Moves Plan Forward to Chop Up Vehicle Safety Airwaves

Alexandre Petrescu <> Tue, 17 December 2019 10:58 UTC

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From: Alexandre Petrescu <>
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Date: Tue, 17 Dec 2019 11:58:39 +0100
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Subject: Re: [ipwave] FCC Moves Plan Forward to Chop Up Vehicle Safety Airwaves
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> BAND WASHINGTON, December 12, 2019—The Federal Communications
> Commission today voted[...]

What does C in C-V2X mean?  Is it Cellular V2X like in 3GPP?  I assume
this is what is meant by C-V2X: point-to-point links from 3GPP.

Or is C-V2X something more like BSM messages put on 802.11 kind of link
(be it OCB or more traditional WiFi)?

What does C-V2X mean entirely?  Is it sending BSM messages or is it also
sending CAM messages (in 3GPP there are only CAM messages AFAIremember).

What are the implementations of C-V2X  and on which hardware from which

Detailing this term is key to understand the plan and to be able to
answer the consultation.  It might be very worrisome as well as it might
be nothing new but a change in terms.

> In the Notice of Proposed Rulemaking, the Commission proposes to 
> designate the lower 45 megahertz of the band for unlicensed uses like
> Wi-Fi. This 45 megahertz sub-band can be combined with existing 
> unlicensed spectrum to provide cutting-edge high-throughput broadband
> applications on channels up to 160 megahertz wide.

It means that 5850MHz-5895MHz would be for WiFi traditional, not OCB,
because it wants to link channels up to 160MHz wide.  The rest of 115MHz
of channel space can only come from the 2.4 and 5.4 bands.  YOu cant
link OCB with non OCB channels.  So this 5850-5895MHz would be
WiFi-not-OCB (traditional WiFi).

> The Commission is proposing to dedicate the remaining 30 megahertz of
> the band for use by transportation and vehicle safety-related 
> communication services. Specifically, in the NPRM, the Commission 
> proposes to revise its rules to provide Cellular Vehicle to 
> Everything (CV2X), an emerging standard for transportation 
> applications, with exclusive access to the upper 20 megahertz of the
>  band.

So, the Commission wants the 5905-5925MHz channels for C-V2X.

> Under the Commission’s current rules, no spectrum is allocated for 
> C-V2X. The NPRM seeks comment on whether to retain the remaining 10 
> megahertz for use by DSRC systems or to dedicate it for C-V2X use.

So, one option is to leave the 5895-5905MHz channel to 802.11-OCB aka
DSRC, or to take that channel away and dedicate it as well for C-V2X.

If they take that 5895-5905MHz away (give it to C-V2X) then they
effectively kill 802.11-OCB altogether, including the use of
IPv6-over-802.11-OCB.  Because 802.11-OCB is specified only for these
bands: 5875-5925MHz.

There are indeed not as many deployments of 802.11-OCB as expected, and
even less IPv6-over-OCB.  But from that to kill 802.11-OCB entirely, it
would be surprising.

For my part, I was more worried about differences between BSM,
CAM/GeoNetworking and LTE-V2X rather than a worries on the spectrum use.
  It is these differences that make it expensive to create a
region-specific OBU for cars.  This is one of the reasons of slow

There are other reasons of slow deployment of OCB that deserve discussion.


Le 17/12/2019 à 01:01, Russ Housley a écrit :
> its mailing list