TOYOTA STRESSES IMPORTANCE OF SHARING
FRAMEWORK FOR 5.9 GHz BAND
A representative of a major automaker plans to testify at a House hearing tomorrow that his company doesn't oppose sharing 5.9 gigahertz band spectrum with unlicensed devices, but he will stress that any such framework must protect dedicated short-range communications (DSRC) applications from interference.
"Toyota is not conceptually opposed to sharing the 5.9 GHz spectrum with unlicensed devices and believes that it may be possible for DSRC and unlicensed devices to co-exist in the band," according to the prepared testimony of John Kenney, principal researcher at the Toyota InfoTechnology Center U.S.A., Inc.
"However, we also believe that the creation of a sharing framework, or the implementation of sharing rules, should not occur unless and until: (1) a viable spectrum sharing technology is identified; and (2) testing verifies that there is no harmful interference from unlicensed devices. Interference that results in delayed or missed driver warnings will undermine the system's entire foundation, rendering it essentially useless and putting the entire future of DSRC technology in the United States at risk. Although we are strongly committed to the technology, the automobile industry cannot responsibly deploy 'safety-of-life' DSRC technology unless the possibility of harmful interference from unlicensed devices is ruled out."
Mr. Kenney and other witnesses are scheduled to appear at a hearing
tomorrow afternoon held by the House communications and technology subcommittee.
In February, the FCC unanimously adopted a notice of proposed rulemaking that proposed to make up to 195 MHz of additional spectrum in the 5 GHz band available for unlicensed use (TRDaily,
Feb. 20).
"In our opinion, Congress made an important and correct distinction in the Middle Class Tax Relief and Job Creation Act as it relates to the 5 GHz band. As you are aware, the law expressly required the FCC to initiate a proceeding to allow unlicensed devices to operate in the
5350-5470 MHz band. By contrast, there was no requirement by Congress for the FCC to initiate a proceeding to allow unlicensed devices in the 5.9 GHz band," Mr. Kenney noted. "Instead, the law required only that the National Telecommunications and Information Administration (NTIA), in consultation with other affected agencies, conduct a study to evaluate known and proposed spectrum sharing technologies and the risk to federal users if unlicensed devices were permitted. We believe that this Congressional distinction is critical and correctly supports the notion that further steps need to be taken before any kind of sharing regime is imposed in the 5.9 GHz band.
"As you are likely aware, the preliminary NTIA study identified specific risk elements with respect to the co-existence of unlicensed devices with DSRC systems in the 5.9 GHz band," Mr. Kenney noted. "The study concluded that more work needed to be done to understand the challenges before the agency could conclude that the band can be safely opened up to Wi-Fi or other unlicensed use. The NTIA has stated its intent to finalize recommendations on the suitability of the band for unlicensed device operation by the end of next year."
He added that "there are unique technical challenges to sharing in the 5.9 GHz band that cannot be ignored. For example: Unlicensed devices currently operating in some other bands detect primary users whose position is most often fixed, such as in the case of radar installations. In these cases, a geolocation database of primary user locations may be sufficient to establish certain areas as safe for unlicensed operation. By contrast, DSRC devices are inherently mobile and can operate almost anywhere. Unlicensed signal detection technologies were not designed to detect, and may not actually be capable of detecting, DSRC signals. Wi-Fi devices currently detect a transition from a channel that is idle to one that is busy based on a 20 MHz Clear Channel Assessment (CCA) function. In contrast, DSRC signals use a 10 MHz channel. As a result, in order for CCA-based DSRC detection to be successful, a Wi-Fi device would need dedicated 10 MHz CCA detectors. * DSRC channel access protocols were not designed with the co-existence of other wireless devices in mind and are not compatible with existing Wi-Fi channel access protocols. For sharing to be possible, it may be necessary for Wi-Fi devices to operate in the 5.9 GHz band only in places and at times when it can reliably be determined that DSRC devices are not present."
But the testimony said that "Toyota is committed to helping to validate a technical sharing solution in the 5.9 GHz band once one has been identified. We have been actively engaged with the Wi-Fi community and other stakeholders who are exploring possible sharing solutions that will alleviate any risk of harmful interference from unlicensed devices. We are also active and engaged members of the recently established Tiger Team through IEEE that is working on possible paths forward on this issue.
"But we're not there yet and it's going to take a bit more time to see if we can get there," Mr. Kenney said. "For now, the good faith efforts that are underway between the automobile companies, the Wi-Fi community, the FCC, the NTIA, and the U.S. DOT should be allowed to proceed. Let the stakeholder community continue to work together to determine the feasibility of sharing between unlicensed devices and DSRC systems."
Mr. Kenney said that, "In the meantime, we encourage the FCC to move forward with its proceedings to open up other bands of spectrum for unlicensed uses, including those within the 5 GHz band, if that is determined to be appropriate. Our request for further evaluation and deliberation applies only to the 5.9 GHz band."
Tom Nagel, senior vice president-strategic initiatives for Comcast Corp., noted the deployment of Wi-Fi hot spots by his company and other cable operators and declared that "the future of Wi-Fi is in the 5 GHz band," citing 2.4 GHz band congestion. But he said it's possible for companies to use the band for gigabit-speed Wi-Fi without causing interference to DSRC operations.
Mr. Nagel said that "Congress and the FCC should not allow incumbents to block needed improvements" to the FCC's 5 GHz band rules. "We will protect existing users from harmful interference. But we cannot afford to allow unnecessary delay. Congress and the FCC should not allow incumbents to refuse to adjust their systems where flexibility would allow substantially more intense use of spectrum."
Mr. Nagel said the FCC should "move ahead with improvements to each individual 5 GHz sub-band as soon as it has the information it needs to devise new rules for that band." He hailed an agreement announced by NTIA and the Department of Defense in which the government said it did not need access to the U-NII [unlicensed-national information infrastructure]-1 band. "As a result, the FCC now has a complete record on the U-NII-1 band and can issue a decision to allow outdoor operations and a higher power level," he said.
Mr. Nagel said that "Comcast and other interested parties have reached out to DSRC interests to discuss how to work together to implement sharing methodologies without delay. We are committed to finding an approach that will both protect DSRC and allow commercially reasonable Wi-Fi deployment. Although the FCC allocated this spectrum to DSRC well over a decade ago, DSRC is still not commercially available. As a consequence, this is a golden opportunity to design both Wi-Fi and DSRC use of the band to allow sharing that will produce the best overall result."
He added that policymakers should ask DSRC interests when their technology will be available, how much of the U-NII-4 spectrum "is actually necessary" and whether radar and other technologies "may be more effective, more cost efficient, and/or more readily available than V2V [vehicle-to-vehicle] and V2I [vehicle-to-infrastructure] technologies?"
Bob Friday, vice president and chief technology officer of Cisco Systems, Inc., said there is demand today for gigabit-speed Wi-Fi in the 5 GHz band. "To be sure, there are some significant technical challenges in the 5 GHz band. It is not cleared spectrum. It contains incumbent uses important for national security and public safety," Mr. Friday acknowledged. "So we have to get this right. And a successful outcome to the FCC's current examination of 5 GHz means that Wi-Fi cannot create harmful interference to those incumbent systems. Cisco will not settle for less." He added that "with leadership from the FCC and NTIA and the cooperation of our industry partners, we remain confident that technological solutions to these challenges will be found."
Julie Knapp, chief of the FCC's Office of Engineering and Technology, said the agency is hopeful that stakeholders can work cooperatively with regulators to enable the 5 GHz band to be used more extensively for Wi-Fi purposes.
"We understand that an extensive amount of research and investment has gone into developing the DSRC over the past decade, and that the automotive industry and proponents of unlicensed use have recently begun evaluating viable sharing scenarios in the 5 GHz band," he said. "A considerable amount of work remains to examine the compatibility between unlicensed devices and these incumbent uses. We are hopeful that all parties will work together to come to technical solutions that will permit unlicensed operations in this band to coexist with DSRC and other systems."
Mr. Knapp emphasized "that the Commission has not proposed to take away any incumbent user's right to operate as a licensed service in the 5 GHz band. As with all unlicensed services, U-NII devices may not cause harmful interference to licensed services, and must accept any harmful interference that they receive. It is my hope that all parties will work together in good faith to overcome these technical and policy challenges, and that we will be able to find a way to effectively share all 295 megahertz of the spectrum I described today."
In his prepared opening statement, Rep. Greg Walden (R., Ore.), the subcommittee's chairman, said, "I am looking forward to hearing from our very qualified witnesses today on both the potential that this spectrum holds to fuel the next generation of unlicensed wireless technologies and the benefits they will bring, but also the technical and economic challenges to making the most of the band. I think I speak for many of my colleagues when I say that we are excited to see the fruits of this subcommittee's labor come to fruition in the form of faster and more abundant Wi-Fi, but not at the expense of existing licensed services. These services can coexist and thanks to the hard work of the industries and agencies represented by our witnesses, we don't have to choose between better Internet access and safer cars."
In her opening statement, Rep. Anna G. Eshoo (D., Calif.), the subcommittee's ranking member, said that "while the 5 GHz band is an important component of a 21st century unlicensed spectrum policy, it is complementary, not a substitute for low-band spectrum below 1 GHz. Simply put, the superior propagation factors found in the television band will unlock new unlicensed innovation, such as rural broadband access that would not be possible in higher bands of spectrum. The time to act is now. The FCC should move expeditiously to harmonize existing rules and make more spectrum available for gigabit Wi-Fi."- Paul Kirby,
paul.kirby@wolterskluwer.com