Re: [ipwave] LTE-V2X term in Problem Statement document

[Jérôme Härri <[e-mail]>]

Hi Alex,

I do not know. What I know is that C-V2X is the general denomination in the US for LTE for V2X services, itself also confusing and misleading...as depending on who talks about it, it is either the sidelink V2X (exclusively) or includes everything: mode 4 (ad-hoc), mode 3 (eNB supervised) and Uu. 

BR,

Jérôme
-----Original Message-----
From: Alexandre Petrescu [mailto:[e-mail]] 
Sent: Wednesday 17 April 2019 15:29
To: Jérôme Härri; [e-mail]; [e-mail]
Subject: Re: [ipwave] LTE-V2X term in Problem Statement document



Le 17/04/2019 à 15:25, Jérôme Härri a écrit :
> Dear Dirk,
> 
> Thanks. I guess we replied with similar thoughts. Now, on your 
> definition, I would also avoid using this:
> 
> LTE-V2X: the transmission of ETSI CAM and DENM messages over IP over a 
> cellular link such as 3GPP 4G – both via base station and directly 
> between vehicles
> 
> JHNOTE: we should not link CAM/DENM on LTE-V2X…these are layered 
> aspect…LTE-V2X can take whatever comes from higher layers, as long as it 
> is packet-based (no streams) and (most likely) periodical (from the 
> semi-persistent scheduling of the LTE Slidelink V2X scheduler), even if 
> this last point can be discussed.
> 
> C-V2X: the transmission of ETSI CAM and DENM messages over IP over a 
> cellular link such as 3G, 4G and successors – both in infrastructure 
> mode (via base station / Uu interface) and ad-hoc mode (direct link / 
> sidelink interface) if available [since sidelink is only specified for 
> 4G/5G]
> 
> JHNOTE: I think we should not use C-V2X, as the denomination ‘C’ is for 
> ‘Cellular’, which might not be fully the case (e.g. LTE Prose mode 4, 
> a.k.a V2X)

Is C-V2X term already defined by Qualcomm?  Or by another SDO?

Alex

> 
> Best Regards,
> 
> Jérôme
> 
> *From:*its [mailto:[e-mail]] *On Behalf Of 
> *[e-mail]
> *Sent:* Wednesday 17 April 2019 14:32
> *To:* [e-mail]; [e-mail]
> *Subject:* Re: [ipwave] LTE-V2X term in Problem Statement document
> 
> Hi Alex,
> 
> I strongly agree with you that we need a precise definition on what we 
> mean with cellular V2X (often denoted as C-V2X in general – so covering 
> LTE and 5G/NR) – especially since – as you correctly pointed out - 3GPP 
> has none such official definition as LTE-V2X or NR-V2X .
> 
> However when defining LTE-V2X we should be aware that there are two 
> different modes of operation for V2X communication in 3GPP cellular 
> systems (as also described in Annex A.5 of PS document 
> https://tools.ietf.org/html/draft-ietf-ipwave-vehicular-networking-08).
> 
> E.g. according to 3GPP TR 21.914 giving a Release 14 (i.e. LTE) 
> Description and Summary of Rel-14 Work Items, but similarly also for 
> 5G/NR or Rel. 15 and higher (here in still draft TR 21.915) the modes of 
> operation are described as
> 
> -Direct V2X communication between UEs over a 3GPP sidelink (PC5 interface)
> 
> -V2X communication over LTE-Uu interface (i.e. via base stations / eNBs)
> 
> In addition there are 2 different modes for PC5/sidelink:
> 
> -in coverage of cellular system with LTE assistance
> 
> -out of coverage: ad-hoc mode w/o assistance … very similar to OCB.
> 
> So I would recommend to specify more exactly what we have in mind.
> 
> LTE-V2X: the transmission of ETSI CAM and DENM messages over IP over a 
> cellular link such as 3GPP 4G – both via base station and directly 
> between vehicles
> 
> Or more general:
> 
> C-V2X: the transmission of ETSI CAM and DENM messages over IP over a 
> cellular link such as 3G, 4G and successors – both in infrastructure 
> mode (via base station / Uu interface) and ad-hoc mode (direct link / 
> sidelink interface) if available [since sidelink is only specified for 
> 4G/5G]
> 
> Or one may even reflect differentiation between those modes in the 
> acronym (which I would not recommend here being not in scope for this 
> document)
> 
> Just my 2 cents
> 
> Kind regards
> 
> Dirk
> 
> *From:*its <[e-mail]> *On Behalf Of *Alexandre Petrescu
> *Sent:* Mittwoch, 17. April 2019 13:18
> *To:* [e-mail]
> *Subject:* [ipwave] LTE-V2X term in Problem Statement document
> 
> Hi IPWAVErs,
> 
> The IPWAVE Problem Statement document uses the term 'LTE-V2X' at one 
> point. ("e.g., IEEE 802.11-OCB and LTE-V2X")
> 
> I would like to suggest to make a careful definition of the term 'LTE-V2X'.
> 
> One would expect the term 'LTE-V2X' to be defined precisely at 3GPP or 
> similar.  But that is not the case.  The 3GPP document that is closest 
> to this term is RP-161298, publicly available, defines the term 
> 'LTE_V2X' (remark underscore '_', instead of dash '-').
> 
> I suggest the addition of the following term in the Problem Statement draft:
> 
> LTE-V2X: the transmission of ETSI CAM and DENM messages over IP over a 
> cellular link such as 3G, 4G and successors.
> 
> Alex
>