5GAA, NGMN argue for cellular, not DSRC, in NHTSA proposal

Out with the old, in with the new, according to several cellular industry groups commenting on the U.S. National Highway Traffic Safety Administration (NHTSA) plan to use dedicated short-range communications (DSRC) to improve road safety.

The deadline was April 13 for the public to comment on the NHTSA’s plan, which proposes requiring vehicle-to-vehicle devices to “speak the same language” through standardized messaging and would require automakers to include V2V technologies in all new light-duty vehicles. Designating a single language would solve the problem of dueling protocols, but opponents argue that DSRC is already outdated and shouldn’t be mandated. In fact, many commenters don’t want to see any specific technology mandated at all.

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The 5GAA, whose founding members include Ericsson, Intel, Huawei, Nokia, Qualcomm, Audi, BMW Group and Daimler AG, prefers Cellular Vehicle-to-Everything (Cellular-V2X) for V2V safety, saying it exceeds the capabilities of DSRC on more than one front. But 5GAA doesn’t want to see any technology mandated.

“Rather than moving forward with the proposed regulation, NHTSA should instead undertake an updated, comprehensive technology neutral analysis of V2V solutions, including DSRC and Cellular-V2X, against the performance requirements in the NPRM,” 5GAA wrote. “Consistent with a technology neutral guiding principle, any such regulation should not require one-way interoperability with a specific technology, or in any way pick technology winners and losers.”

Next Generation Mobile Networks (NGMN), whose U.S. board members include AT&T, Sprint, T-Mobile, US Cellular, Verizon and Ligado Networks, commented in much the same vein, saying its V2X Task Force recommends the U.S. Department of Transportation (DoT) be technology neutral in the rulemaking. Cellular technologies beginning with 3GPP Release 14 could offer a technical and market-driven solution with a clear evolution path, they say.

NGMN recognizes the efforts taken over the past 10 years to develop and test use cases based on DSRC technology, but it notes that cellular-based communication technology has already been widely deployed within vehicles, not only for information and entertainment purposes but also for maintaining and increasing safety and security.

In its remarks, CTIA also disputes the NHTSA’s assessment of the reliability of cellular networks for vehicle-based communications, noting that LTE latency rates are roughly 10 milliseconds over the air and 5G latency rates will be even lower, targeted to be five to 10 times lower.

“5G is not aspirational,” CTIA wrote, adding that the FCC itself declared the deployment of 5G by as early as 2020 as a national priority. Since 5G infrastructure, particularly small cell sites and fiber, will be built close to roadways, it will be readily available to support the full range of V2V and vehicle-to-infrastructure (V2I) communications at low latency, especially in high-density areas with great demands for data throughput from a large number of users, the organization said.

5G Americas says DSRC relies on roadside units that are not ubiquitously deployed in the U.S., whereas cellular networks are ubiquitous, including in most rural areas. “At the physical layer, DSRC has several inefficiencies due to the asynchronous nature of the system, resulting in reduced range, robustness and reliability and high latency,” said 5G Americas President Chris Pearson in a filing. “Currently there is no activity in the IEEE 802.11 standards body to study a next-generation DSRC technology that will meet the requirements of more advanced V2X use cases such as automated vehicles.”

Cellular networks could be used to provide backhaul to the roadside units and can extend the V2X range from the 300 meters that DSRC offers to several kilometers or more, providing earlier notifications to drivers and their vehicles, 5G Americas said.

“A voluntary path to enhance the long-term safety of U.S. roadways is preferable to mandating decades’ old technology that is not likely to evolve, and therefore might not deliver benefits comparable to C-V2X,” Pearson concluded.

The NHTSA has said it will review the submitted comments and adjust its proposal as appropriate before issuing a final rule.