Qualcomm Outlines Connected Cars (C-V2X) Safety Features, Stresses On Interference Protection

Ramish Zafar

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C-V2X design changes over DSRC, more interference limits and Qualcomm's motives for urging a speedy deployment

Qualcomm's Senior Vice President of spectrum strategy and technology policy.

W: Will C-V2X offloading less time-critical applications to cellular networks in times of congestion affect the technology's safety and performance?

D: "The fact that C-V2X has these two modes of operations, one the sideline mode where cars are talking to cars and cars are talking to infrastructure directly and C-V2X is about this other network-based mode. You know we don't, that's very integral to the design of C-V2X and the whole premise is that very time-sensitive, very latency-sensitive operations would be done in the direct mode in the PC5 mode. Whereas broadcast messages, or the things that are less time-sensitive would be done in the network mode or the so called VU mode. So if you're asking does that, does the fact that C-V2X has these two modes does that pose any issue for safety then the answer is no. That's been baked into the design of C-V2X all along, if anything it has a very positive effect because we're not using the 5.9 GHz spectrum for the communications that don't need to be done in a time-sensitive manner. So you're segregating communications [into] those that time-sensitive or done in the 5.9 band, in the direct mode. Those that are not time-sensitive are done in the network mode you know using U2U and that was a very sound design to C-V2X."

W: The new FCC rules remove the ITS Control Channel since they allocate its spectrum for unlicensed uses. Since Channel 178 (the Control Channel) is used for public safety messages and for coordinating other channels, will removing this affect C-V2X’s safety features?

D: "No, it has no impact on C-V2X safety features. So for one thing let's be clear there are no cars, so that assignment of channels is based on the way the DSRC standard was written. C-V2X's standard isn't written that way at all. You know we don't have a 10MHz channel that's solely used as a control channel. We don't have channels that are solely used for higher power versus lower power. Our design's very different. So the fact that the FCC in allocating the spectrum for C-V2X didn't superimpose DSRC standards on top of it makes perfect sense and you know is totally in keeping with allocating the spectrum for C-V2X. But nothing in the FCC ruling poses any kind of problem or obstacle or hindrance for the use of C-V2X to enhance safety."

W: Current ITS standards have a message priority hierarchy with communications involving the safety of life having priority access. Communications involving public safety have the next priority level that assumes that roadside units operated by state or local governmental entities are engaged in public safety priority communications. Does Qualcomm support to maintain this order for the upgraded standards as well?

D: "Yeah so I think there's some misunderstanding. So reserving a channel for safety that's again a relic of the way the DSRC standard was written. The C-V2X standard is not written that way. We don't reserve channels that way. We allocate in a much similar way a cellular system spectrum can be allocated dynamically based on capacity needs and demand you know that's the way C-V2X will work using the 20MHz in allocating the capacity between vehicle-to-vehicle and vehicle to infrastructure communications, So there's a fact there isn't a "safety-channel" in C-V2X is not a meaningful distinction between C-V2X and DSRC.

"That's just a relic again of the fact that DSRC standard was written differently than C-V2X standard. That there's no diminution in the importance of safety in comparing C-V2X to DSRC. So the fact that there isn't a channel denominated as a safety channel does not mean C-V2X in any way shape or form is less focused on safety or places a lower priority on safety or anything like that. In fact it's just the opposite, the way that C-V2X will operate in the spectrum you know everything about it will be to enhance safety. There won't be any part of it that isn't used to enhance safety. I think it's just semantics in the way the different standards are written."

John Kuzin, Vice President and Regulatory Counsel at Qualcomm.

W: In addition to Qualcomm’s readiness to deploy C-V2X solutions now, what other factors are behind the company stressing immediate deployment? Any competitive motivations? Or are there any other factors in play?

D: "Well the headline here is the spectrum is now available. The FCC has made the spectrum available and before the FCC ruling the spectrum wasn't available and the FCC rules didn't allow deployment of C-V2X. So you know I would think that everyone in the auto industry would take a fresh look at the whole situation in the wake of the FCC ruling obviously again you know we're hoping to see improvement on the interference protections. That's...you know we've been very clear about that, but I would think that anyone who is comparing the two technologies and deciding what to deploy, you know now C-V2X is the technology of the future, for the upper 30MHz, not DSRC.

"So I would think that most stakeholders in the auto industry would take a step back and would you know really re-evaluate the situation in light of this major FCC ruling. And we're hopeful, we remain very very hopeful that if folks do that, if they would want to move ahead now that the spectrum is made available for C-V2X."

W: In its Further Notice of Proposed Rulemaking, the FCC, the Commission asks for comment on OOBE limits for adjacent bands, which is the lower limit of the C-V2X band which touches the upper limit of the unlicensed band. So what limits does Qualcomm have in mind for adjacent bands, if any, for the new spectrum split since these limits weren't present in the previous allocation since DSRC was the only technology being used?

J: "So if you look in the FNPRM the FCC makes reference to a March 8th 5GAA filing. It was the 5GAA's comments on the December 2019 NPRM and they are...it's a full suite of technical proposals that includes the OOBE that C-V2X would operate under in the upper 30MHz of the channel."

W: Moving to my final question for C-V2X's deployment timeline. In explaining the merit of deploying the entire spectrum for ITS, the AAI argued before the FCC that “[W]ithin 5 years, a total of at least 5 million radios on vehicles and roadway infrastructure will have been deployed, including any previous V2X deployments,” but only if the entire 5.9 GHz band is preserved for ITS.353. Does Qualcomm have a similar guesstimate on how many radios it might be able to deploy?

D: "As many as possible [laughs]. I don't think we have publicly talked about you know a specific number so I don't think we have a number that we can share but obviously, we're excited about it and you know we are looking forward to selling as many as chips for radios going to cars absolutely as quickly as possible."

W: Moving to my final question for today's interview, does Qualcomm agree with 5GAA’s proposal to eliminate the output power requirement and increase the OBU (on board unit) EIRP limit to 33 dBm.

J: "The short answer is yes."


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